Dipentene dimercaptan compositions and use thereof as a mining chemical collector

ABSTRACT

The present invention shows polythiol compositions containing dipentene dimercaptans and intermolecular sulfide compounds, as well as mining chemical collector compositions containing such polythiol compositions. Flotation processes for recovering metals, such as copper and molybdenum, from ores using the mining chemical collector compositions also are shown.

BACKGROUND OF THE INVENTION

The present invention relates generally to polythiol compositionscontaining dipentene dimercaptans and intermolecular sulfide compounds,and to methods for producing such polythiol compositions. Thesepolythiol compositions can be used in mining chemical collectorcompositions, and the collector compositions can be used in flotationprocesses for recovering metals from ores.

SUMMARY OF THE INVENTION

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the detaileddescription. This summary is not intended to identify required oressential features of the claimed subject matter. Nor is this summaryintended to be used to limit the scope of the claimed subject matter.

Various mining chemical collector compositions and polythiolcompositions comprising sulfur-containing compounds are disclosedherein. In one embodiment, a collector composition of this invention cancomprise a polythiol composition and water, while in another embodiment,a collector composition can comprise a polythiol composition and a pHcontrol agent, and in yet another embodiment, a collector compositioncan comprise a polythiol composition and a frothing agent. Accordingly,a particular collector composition of this invention can comprise apolythiol composition, a frothing agent, a pH control agent, and water.

In these and other embodiments, suitable polythiol compositionscomprising sulfur-containing compounds are disclosed, and thesulfur-containing compounds can comprise (i) dipentene dimercaptancompounds and (ii) at least 4% of a heavy fraction comprisingintermolecular sulfide compounds having at least one thiol sulfur group(—SH), at least one intermolecular sulfide group (—S—), and at least twosubstituted cyclohexyl groups. A representative dipentene dimercaptancompound can have the following structure:

Flotation processes for the recovery of a metal (or metals) from an orealso are disclosed herein. These processes can comprise contacting theore with any of the collector compositions and/or any of the polythiolcompositions disclosed herein. The metal can comprise any suitabletransition metal, such as copper, molybdenum, and the like, as well ascombinations of two or more metals.

Both the foregoing summary and the following detailed descriptionprovide examples and are explanatory only. Accordingly, the foregoingsummary and the following detailed description should not be consideredto be restrictive. Further, features or variations can be provided inaddition to those set forth herein. For example, certain embodiments canbe directed to various feature combinations and sub-combinationsdescribed in the detailed description.

DEFINITIONS

To define more clearly the terms used herein, the following definitionsare provided. Unless otherwise indicated, the following definitions areapplicable to this disclosure. If a term is used in this disclosure butis not specifically defined herein, the definition from the IUPACCompendium of Chemical Terminology, 2^(nd) Ed (1997) can be applied, aslong as that definition does not conflict with any other disclosure ordefinition applied herein, or render indefinite or non-enabled any claimto which that definition is applied. To the extent that any definitionor usage provided by any document incorporated herein by referenceconflicts with the definition or usage provided herein, the definitionor usage provided herein controls.

Herein, features of the subject matter can be described such that,within particular aspects and/or embodiments, a combination of differentfeatures can be envisioned. For each and every aspect, and/orembodiment, and/or feature disclosed herein, all combinations that donot detrimentally affect the designs, compositions, processes, and/ormethods described herein are contemplated with or without explicitdescription of the particular combination. Additionally, unlessexplicitly recited otherwise, any aspect, and/or embodiment, and/orfeature disclosed herein can be combined to describe inventive featuresconsistent with the present disclosure.

While compositions and methods are described herein in terms of“comprising” various components or steps, the compositions and methodscan also “consist essentially of” or “consist of” the various componentsor steps, unless stated otherwise. For example, a collector compositionconsistent with embodiments of the present invention can comprise;alternatively, can consist essentially of; or alternatively, can consistof; a polythiol composition, a pH control agent, a frothing agent, andwater.

The terms “a,” “an,” and “the” are intended to include pluralalternatives, e.g., at least one. For instance, the disclosure of “asolvent,” “a transition metal,” etc., is meant to encompass one, ormixtures or combinations of more than one, solvent, transition metal,etc., unless otherwise specified.

Generally, groups of elements are indicated using the numbering schemeindicated in the version of the periodic table of elements published inChemical and Engineering News, 63(5), 27, 1985. In some instances, agroup of elements can be indicated using a common name assigned to thegroup; for example, alkali metals for Group 1 elements, alkaline earthmetals for Group 2 elements, transition metals for Group 3-12 elements,and halogens or halides for Group 17 elements.

For any particular compound or group disclosed herein, any name orstructure presented is intended to encompass all structural isomers,conformational isomers, regioisomers, stereoisomers, and mixturesthereof that can arise from a particular set of substituents, unlessotherwise specified. The name or structure also encompasses allenantiomers, diastereomers, and other optical isomers (if there areany), whether in enantiomeric or racemic forms, as well as mixtures ofstereoisomers, as would be recognized by a skilled artisan, unlessotherwise specified. For example, a general reference to hexene (orhexenes) includes all linear or branched, acyclic or cyclic, hydrocarboncompounds having six carbon atoms and 1 carbon-carbon double bond;pentane includes n-pentane, 2-methyl-butane, and 2,2-dimethylpropane; ageneral reference to a butyl group includes an n-butyl group, asec-butyl group, an iso-butyl group, and a t-butyl group; a generalreference to cyclododecatriene includes all isomeric forms (e.g.,trans,trans,cis-1,5,9-cyclododecatriene, andtrans,trans,trans-1,5,9-cyclododecatriene, among other dodecatrienes);and a general reference to 2,3-pentanediol includes 2R,3R-pentanediol,2S,3S-pentanediol, 2R,3S-pentanediol, and mixtures thereof.

In one embodiment, a chemical “group” can be defined or describedaccording to how that group is formally derived from a reference or“parent” compound, for example, by the number of hydrogen atoms removedfrom the parent compound to generate the group, even if that group isnot literally synthesized in such a manner. These groups can be utilizedas substituents, can be coordinated or bonded to metal atoms, or can besubstituted or unsubstituted. By way of example, an “alkyl group”formally can be derived by removing a hydrogen atom (one or more, asnecessary for the particular group) from a carbon atom of an alkane. Thedisclosure that a substituent, ligand, or other chemical moiety canconstitute a particular “group” implies that the well-known rules ofchemical structure and bonding are followed when that group is employedas described. When describing a group as being “derived by,” “derivedfrom,” “formed by,” or “formed from,” such terms are used in a formalsense and are not intended to reflect any specific synthetic methods orprocedures, unless specified otherwise or the context requiresotherwise.

As used herein, “thiol sulfur” means sulfur from a —SH group (thiolgroup), while “sulfide sulfur” means sulfur from a —S— group (sulfidegroup). Sulfide sulfur groups encompass both intermolecular sulfidegroups and intramolecular sulfide groups. The term “intermolecularsulfide” as used herein refers to sulfide bonds formed by a reactionbetween two molecules. The term “intramolecular sulfide” refers tosulfide bonds formed by a reaction within a single molecule.

As used herein, a “polythiol composition” refers to a compositioncomprising polythiol molecules. Polythiol molecules refer to moleculeshaving two or more thiol groups per molecule (e.g., 2, 3, etc., thiolgroups). For illustrative purposes, in addition to polythiol moleculeshaving 2 SH groups, a polythiol composition also can contain compoundshaving only 1 thiol group, compounds having only one sulfur atom presentas sulfide sulfur, etc. Furthermore, such polythiol compositions cancontain other compounds and components, non-limiting examples of whichcan include solvents and other materials, as well as residual limonenefrom which the polythiol composition may be derived.

In some instances, the polythiol composition is described, while inothers, the sulfur-containing compounds (i.e., having at least 1 sulfuratom present as thiol sulfur or sulfide sulfur) of the polythiolcomposition are described. Consequently, within this disclosure,properties associated with polythiol compositions can includecontributions from the limonene from which the compositions can beformed, as well as other reactants and by-products. In somecircumstances, it can be beneficial to refer only to thesulfur-containing compounds, as if the limonene, other reactants,by-products, and/or solvent are not present in the composition.Accordingly, within this disclosure, the term “sulfur-containingcompounds,” used in conjunction with the polythiol composition, refersto organic compounds within the composition that contain at least onesulfur atom present in a thiol sulfur group or sulfide sulfur group, andexcludes any non-sulfur-containing compound (e.g., limonene reactantand/or solvent, among others), and excludes any sulfur-containingreactant (e.g., H₂S). In sum, a polythiol composition can include allmaterials in a composition comprising polythiol molecules, while thesulfur-containing compounds refer only to the compounds within thepolythiol composition having at least sulfur atom present in a —SH or a—S— group.

As utilized herein, the mercaptan equivalent weight (SHEW) equals themolecular weight of a particular mercaptan molecule divided by thenumber of mercaptan groups in the mercaptan molecule, and has the unitsof grams/equivalent (g/eq). When referring to a composition ofsulfur-containing compounds, the SHEW refers to an average SHEW of allthe sulfur-containing compounds in the composition.

The terms “contact product,” “contacting,” and the like, are used hereinto describe compositions and methods wherein the components arecontacted together in any order, in any manner, and for any length oftime, unless otherwise specified. For example, the components can becontacted by blending or mixing. Further, unless otherwise specified,the contacting of any component can occur in the presence or absence ofany other component of the compositions and methods described herein.Combining additional materials or components can be done by any suitablemethod. Further, the term “contact product” includes mixtures, blends,solutions, slurries, reaction products, and the like, or combinationsthereof. Although “contact product” can, and often does, includereaction products, it is not required for the respective components toreact with one another. Similarly, the term “contacting” is used hereinto refer to materials which can be blended, mixed, slurried, dissolved,reacted, treated, or otherwise contacted in some other manner.Therefore, the term “contacting” encompasses the “reacting” of two ormore components, and it also encompasses the “mixing” or “blending” oftwo or more components that do not react with one another.

Although any methods and materials similar or equivalent to thosedescribed herein can be used in the practice or testing of theinvention, the typical methods and materials are herein described.

All publications and patents mentioned herein are incorporated herein byreference for the purpose of describing and disclosing, for example, theconstructs and methodologies that are described in the publications,which might be used in connection with the presently describedinvention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides mining chemical collector compositionscontaining polythiol compositions derived from limonene. While notwishing to be bound by theory, a potential benefit of these collectorcompositions, which comprise sulfur-containing compounds, is lessobjectionable odor, as compared to other collector compositions that donot comprise the polythiol heavy fraction, sulfide group (—S— group)functionality, and other compositional attributes disclosed herein.Moreover, in contrast to the prevailing knowledge in the mining chemicalcollector arts, in which it is believed that good collectors have onlyone functional group (e.g., like a mercaptan or thiol group) connectedto a long-chain hydrocarbon (e.g., a C₁₂ hydrocarbon), it wasunexpectedly found in this invention that the compositions disclosedherein provide excellent collector performance in spite of containingtwo or more functional groups (e.g., sulfide groups, mercaptan or thiolgroups), as well as short hydrocarbon chains therebetween.

Polythiol Compositions

Polythiol compositions consistent with embodiments of the inventiondisclosed and described herein can comprise sulfur-containing compounds,and these sulfur-containing compounds can comprise dipentene dimercaptancompounds and at least 4% of a heavy fraction comprising intermolecularsulfide compounds having at least one thiol sulfur group (—SH), at leastone intermolecular sulfide group (—S—), and at least two substitutedcyclohexyl groups.

Dipentene dimercaptan compounds can include the following representativecyclohexyl-containing structure:

Unless otherwise specified, the name and structural formula above, anyother names and structural formulas disclosed herein, and any group,species, or compound disclosed herein are not designed to showstereochemistry or isomeric positioning of the different moieties,although such compounds are contemplated and encompassed by these namesand/or formulas and/or structures, unless stated otherwise. Forinstance, the disclosure of “dipentene dimercaptan compounds” is meantto encompass cyclohexyl-containing compounds such as the Markovnikovisomer shown below, which can be produced by the addition of H₂S tolimonene, as would be recognized by those of skill in the art:

The heavy fraction can comprise intermolecular sulfide compounds havingat least one thiol sulfur group (—SH), at least one intermolecularsulfide group (—S—), and at least two substituted cyclohexyl groups. Inparticular embodiments of this inventions, the heavy fraction cancomprise intermolecular sulfide compounds having two thiol sulfur groups(—SH), one intermolecular sulfide group (—S—), and two substitutedcyclohexyl groups. Further, each substituted cyclohexyl group can have athiol group substituent directly on a ring carbon of the cyclohexylgroup or an alkylthiol substituent with a carbon atom of the alkylbonded to a ring carbon of the cyclohexyl group.

Illustrative and non-limiting examples of these sulfur-containingcompounds having two thiol sulfur groups (—SH), one intermolecularsulfide group (—S—), and two substituted cyclohexyl groups, can includethe following compounds:

Moreover, as would be recognized by those of skill in the art, thesulfur-containing compounds of the polythiol composition can compriseother intermolecular sulfide isomers having the same molecular formulasas these intermolecular sulfide compounds, and such isomeric compoundsalso are encompassed herein.

In these and other embodiments, the polythiol compositions comprisingsulfur-containing compounds disclosed herein can further comprise one ormore sulfide molecules having two thiol sulfur groups (—SH), twointermolecular sulfide groups (—S—), and three substituted cyclohexylgroups. Illustrative and non-limiting examples of thesesulfur-containing compounds having two thiol sulfur groups (—SH), twointermolecular sulfide groups (—S—), and three substituted cyclohexylgroups, can include the following compounds:

Moreover, as would be recognized by those of skill in the art, thesulfur-containing compounds of the polythiol composition can compriseother isomers having the same molecular formulas as these compoundshaving two intermolecular sulfide groups, and such isomeric compoundsare encompassed herein.

Unless otherwise indicated, the compositional aspects of these polythiolcompositions (or of the sulfur-containing compounds of the compositions)are disclosed in GC area % (area percentage determined using a GasChromatograph with a F.I.D. detector, as described herein), because suchpolythiol compositions are generally analyzed or evaluated in thismanner. While not wishing to be bound by this theory, it is believedthat the amount in area % is very similar to the amount in wt. %, butthese respective amounts are not identical or exactly interchangeable.

The illustrative and non-limiting examples of polythiol compositionscomprising sulfur-containing compounds provided hereinabove also canhave any of the characteristics or properties provided below, and in anycombination.

In an embodiment, the sulfur-containing compounds of the polythiolcomposition can contain at least 4%, at least 5%, or at least 6% of theheavy fraction (i.e., comprising intermolecular sulfide compounds).Suitable non-limiting ranges for the amount of the heavy fraction, basedon the sulfur-containing compounds of the composition, can include thefollowing ranges: from 4% to 30%, from 4% to 25%, from 4% to 15%, from5% to 25%, from 5% to 20%, from 5% to 15%, from 6% to 25%, from 6% to20%, or from 6% to 15%. Other appropriate ranges for the amount of theheavy fraction containing intermolecular sulfide compounds are readilyapparent from this disclosure.

In an embodiment, the amount of dipentene dimercaptan compounds, basedon the sulfur-containing compounds of the polythiol composition oftencan fall within a range from 50% to 95%, such as from 50% to 92%, orfrom 50% to 90%. In some embodiments, the dipentene dimercaptancompounds can be from 60% to 95%, from 60% to 92%, from 60% to 90%, from70% to 95%, from 70% to 92%, from 80% to 95%, or from 80% to 92%, basedon the sulfur-containing compounds present in the polythiol composition.Other appropriate ranges for the amount of the dipentene dimercaptancompounds are readily apparent from this disclosure.

Generally, the polythiol compositions can contain minimal amounts ofmonosulfur compounds. Illustrative and non-limiting examples of suchmonosulfur compounds can include the following structures:

For instance, the sulfur-containing compounds of the polythiolcomposition can have a maximum amount of monosulfur compounds (e.g.,dipentene monomercaptan) of less than or equal to 5%, less than or equalto 4%, less than or equal to 3%, less than or equal to 2%, less than orequal to 1%, less than or equal to 0.5%, or less than or equal to 0.25%.Other appropriate ranges for the amount of the monosulfur compounds arereadily apparent from this disclosure.

Generally, the polythiol compositions can contain minimal amounts ofsulfur-free olefin-containing compounds, such as limonene. In someembodiments, the amount of sulfur-free olefin-containing compounds inthe polythiol composition can be less than or equal to 2%, less than orequal to 1%, less than or equal to 0.5%, less than or equal to 0.25%,less than or equal to 0.1%, or less than or equal to 0.05%. Otherappropriate ranges for the amount of the sulfur-free olefin-containingcompounds are readily apparent from this disclosure.

In an embodiment, the sulfur-containing compounds of the polythiolcomposition can have a minimum average thiol sulfur to sulfide sulfurweight ratio of 3:1 or 5:1; additionally or alternatively, thesulfur-containing compounds can have a maximum average thiol sulfur tosulfide sulfur weight ratio of 100:1 or 75:1. Therefore, suitablenon-limiting ranges for the average thiol sulfur to sulfide sulfurweight ratio can include the following ranges: from 3:1 to 100:1, from3:1 to 75:1, from 3:1 to 50:1, from 5:1 to 100:1, from 5:1 to 75:1, from5:1 to 50:1, from 10:1 to 100:1, from 10:1 to 75:1, or from 10:1 to50:1. Other appropriate ranges for the average thiol sulfur to sulfidesulfur weight ratio are readily apparent from this disclosure.

The polythiol compositions can be further characterized by the amount ofsulfide sulfur (sulfur from a —S— group) present in thesulfur-containing compounds of the composition. For instance,sulfur-containing compounds of the composition can have an average offrom 0.1 wt. % to 10 wt. % sulfide sulfur. These percentages are basedon the total sulfur-containing compounds of the composition, regardlessof the number of thiol and/or sulfide groups. In certain embodiments,the sulfur-containing compounds of the polythiol composition can have anaverage sulfide sulfur content in a range from 0.1 to 5 wt. %, from 0.25to 5 wt. %, from 0.5 to 5 wt. %, from 1 to 5 wt. %, from 0.25 to 3 wt.%, from 0.5 to 3 wt. %, from 0.75 to 7 wt. %, or from 0.75 to 4 wt. %.Other appropriate ranges for the average sulfide sulfur content arereadily apparent from this disclosure.

Moreover, the polythiol compositions can be further characterized by theamount of thiol sulfur (sulfur from a —SH group) present in thesulfur-containing compounds of the composition. For example,sulfur-containing compounds of the composition can have an average offrom 26 wt. % to 31 wt. % thiol sulfur. These percentages are based onthe total sulfur-containing compounds, regardless of the number of thioland/or sulfide groups. In particular embodiments, the sulfur-containingcompounds of the polythiol composition can have an average thiol sulfurcontent of the sulfur-containing compounds that includes the followingranges: from 27 to 31 wt. %, from 27 to 30.5 wt. %, from 27 to 30.3 wt.%, from 29 to 31 wt. %, from 29 to 30.5 wt. %, from 29 to 30.2 wt. %,from 28 to 30.5 wt. %, or from 28 to 30.3 wt. %. Other appropriateranges for the average thiol sulfur content are readily apparent fromthis disclosure.

Consistent with particular embodiments of this invention, the polythiolcompositions can be further characterized by the mercaptan equivalentweight (or SHEW) of the composition. For instance, the minimum SHEW ofsulfur-containing compounds of the composition can be 104 or 105, whilethe maximum SHEW of sulfur-containing compounds of the composition canbe 125 or 120 g/eq. Therefore, suitable non-limiting ranges for the SHEWof the sulfur-containing compounds can include the following ranges:from 104 to 125, from 104 to 120, from 104 to 118, from 105 to 125, from105 to 120, or from 105 to 118 g/eq. Other appropriate ranges for theSHEW are readily apparent from this disclosure.

An illustrative and non-limiting example of a polythiol compositionconsistent with the present invention can contain sulfur-containingcompounds comprising from 60% to 95% of dipentene dimercaptan compounds,from 4% to 25% of the heavy fraction (i.e., comprising intermolecularsulfide compounds), and less than or equal to 4% of monosulfurcompounds. Another illustrative and non-limiting example of a polythiolcomposition consistent with the present invention can containsulfur-containing compounds comprising from 70% to 92% of dipentenedimercaptan compounds, from 5% to 15% of the heavy fraction (i.e.,comprising intermolecular sulfide compounds, and less than or equal to1% of monosulfur compounds. As would be readily recognized by those ofskill in the art, the total of these components will be less than orequal to 100%.

While not wishing to be bound by the following theory, it is believedthat a potential and unexpected benefit of the polythiol compositionsdisclosed herein (and the sulfur-containing compounds of the polythiolcompositions disclosed herein) is less objectionable or offensive odor,as compared to other polythiol compositions that do not comprisesulfur-containing compounds with a sulfide group (—S— group), and/orthat contain higher amounts of materials lighter than dipentenedimercaptans, and/or that contain higher amounts of materials withshorter GC retention times, and/or that contain higher amounts ofmonosulfur materials.

While not being limited thereto, the polythiol compositions disclosedherein can be polythiol compositions derived from limonene. In someembodiments, the polythiol compositions disclosed herein can be producedby any process described herein. For instance, these polythiolcompositions can be produced by a process comprising contactinglimonene, H₂S, and optionally, a phosphite compound; and forming thepolythiol composition. The molar ratio of H₂S to carbon-carbon doublebonds of the limonene can be in a range, for example, from 2:1 to 500:1,from 2:1 to 50:1, or from 5:1 to 35:1. Additional information onprocesses for producing such polythiol compositions is provided herein.

Processes for Producing Polythiol Compositions

In accordance with certain embodiments of this invention, a process forproducing a polythiol composition can comprise contacting limonene, H₂S,and optionally, a phosphite compound; and forming the polythiolcomposition. Generally, the features of the process (e.g., the use ofthe phosphite compound, the hydrogen sulfide to carbon-carbon doublebond ratio, the components of and/or features of the polythiolcomposition, and the conditions under which the polythiol composition isformed, among others) are independently described herein and thesefeatures can be combined in any combination to further describe thedisclosed process.

In an embodiment, the contacting step (step 1 of the process) cancomprise contacting limonene, H₂S, and additional unrecited materials(e.g., a solvent). In other embodiments, the contacting step can consistessentially of contacting limonene and H₂S; or alternatively, consist ofcontacting limonene and H₂S. In some embodiments, the contacting step(step 1 of the process) can comprise contacting the limonene, H₂S, theoptional phosphite compound, and additional unrecited materials (e.g., asolvent). In other embodiments, the contacting step can consistessentially of contacting limonene, H₂S, and the optional phosphitecompound or, alternatively, consist of contacting limonene, H₂S, and theoptional phosphite compound. Likewise, additional materials or featurescan be employed in the forming step (step 2 of the process). Forinstance, the formation of the polythiol composition can occur in thepresence of ultraviolet light, discussed further herein. Moreover, it iscontemplated that when the processes for forming polythiol compositionsutilize a phosphite compound, the processes can employ more than onephosphite compound. In some embodiments, the contacting step (step 1)and the forming step (step 2) can occur simultaneously; alternatively,the contacting step (step 1) and the forming step (step 2) can occurseparately; or alternatively, the contacting step (step 1) and theforming step (step 2) can occur sequentially.

In the processes disclosed herein, the minimum molar ratio of H₂S tocarbon-carbon double bonds of the limonene can be 2:1, 3:1, 5:1, or 8:1,while the maximum molar ratio of H₂S to carbon-carbon double bonds ofthe limonene can be 500:1, 150:1, 100:1, 50:1, 35:1, or 25:1. Therefore,suitable ranges for the ratio of H₂S to carbon-carbon double bonds ofthe limonene can include, but are not limited to, the following ranges:from 2:1 to 500:1, from 2:1 to 150:1, from 2:1 to 50:1, from 2:1 to25:1, from 3:1 to 100:1, from 3:1 to 50:1, from 3:1 to 35:1, from 5:1 to500:1, from 5:1 to 100:1, from 5:1 to 35:1, from 5:1 to 25:1, from 8:1to 500:1, from 8:1 to 150:1, from 8:1 to 50:1, from 8:1 to 35:1, or from8:1 to 25:1.

Generally, without being limited to theory, an increase in the ratio ofH₂S to carbon-carbon double bonds can be used to increase the averagethiol sulfur to sulfide sulfur molar ratio and/or the average thiolsulfur content of the sulfur-containing compounds in the polythiolcompositions disclosed herein. In contrast, without being limited totheory, a decrease in the ratio of H₂S to carbon-carbon double bondsgenerally can be used to increase the mercaptan equivalent weight and/orthe average sulfide sulfur content of the sulfur-containing compounds inthe polythiol compositions disclosed herein.

When the phosphite compound is used in the processes disclosed herein,the minimum molar ratio of the phosphite compound to carbon-carbondouble bonds of the limonene can be 0.0005:1, 0.001:1, 0.005:1, or0.006:1, while the maximum molar ratio of the phosphite compound tocarbon-carbon double bonds of the limonene can be 0.1:1, 0.075:1, or0.05:1. Therefore, suitable ranges for the molar ratio of the phosphitecompound to carbon-carbon double bonds of the limonene can include, butare not limited to, the following: from 0.0005:1 to 0.1:1, from 0.0005:1to 0.075:1, from 0.0005:1 to 0.05:1, from 0.001:1 to 0.1:1, from 0.001:1to 0.075:1:1, from 0.001:1 to 0.05:1, from 0.005:1 to 0.1:1, from0.005:1 to 0.05:1, from 0.006:1 to 0.001:1, from 0.006:1 to 0.05:1, from0.008:1 to 0.05:1, from 0.008:1 to 0.04:1, from 0.01:1 to 0.1:1, or from0.01:1 to 0.05:1.

Independently, steps 1 and 2 of the process for forming a polythiolcomposition can be conducted at a variety of temperatures, pressures,and time periods. For instance, the temperature at which the limonene,H₂S, and the phosphite compound (if used) are initially contacted can bethe same as, or different from, the temperature at which the polythiolcomposition is formed. As an illustrative example, in step 1, thelimonene, H₂S, and the phosphite compound (if used) can be contactedinitially at temperature T1 and, after this initial combining, thetemperature can be increased to a temperature T2 to allow the formationof the polythiol composition. Likewise, the pressure can be different instep 1 than in step 2. Often, the time period in step 1 is referred toas the contact time, while the time period in step 2 is referred to asthe reaction time. The contact time and the reaction time can bedifferent; alternatively, the contact time and the reaction time can bethe same.

In an embodiment, step 1 of the process for forming a polythiolcomposition can be conducted at a temperature in a range from −30° C. to150° C.; alternatively, from −20° C. to 130° C.; alternatively, from−10° C. to 100° C.; alternatively, from −5° C. to 80° C.; alternatively,from 0° C. to 60° C.; or alternatively, from 10° C. to 45° C. In theseand other embodiments, after the initial contacting, the temperature canbe changed, if desired, to another temperature for the formation of thepolythiol composition. Accordingly, step 2 can be conducted at atemperature in a range from −30° C. to 150° C.; alternatively, from −20°C. to 130° C.; alternatively, from −10° C. to 100° C.; alternatively,from −5° C. to 80° C.; alternatively, from 0° C. to 60° C.; oralternatively, from 10° C. to 45° C. These temperature ranges also aremeant to encompass circumstances where the forming step can be conductedat a series of different temperatures, instead of at a single fixedtemperature, falling within the respective ranges.

In an embodiment, step 1 and/or step 2 of the process of forming apolythiol composition can be conducted at a total reactor pressure in arange from 30 to 1500 psig, such as, for example, from 50 to 1500 psig.In some embodiments, the polythiol formation in step 2 can be conductedat total reactor pressure in a range from 50 to 1500 psig;alternatively, from 50 to 1000 psig; alternatively, from 50 to 750 psig;alternatively, from 50 to 500 psig; or alternatively, from 100 to 500psig.

The contact time in step 1 of the process is not limited to anyparticular range. That is, the limonene, H₂S, and the phosphite compound(if used) can be initially contacted rapidly, or over a longer period oftime, before commencing the reaction and/or the formation of thepolythiol composition in step 2. Hence, step 1 can be conducted, forexample, in a time period ranging from as little as about 1-30 secondsto as long as about 1-6 hours. In some embodiments, the contact time canbe in a range from 15 minutes to 3 hours, or from 30 minutes to 2 hours.The appropriate reaction time for the formation of the polythiolcomposition in step 2 can depend upon, for example, the reactiontemperature and the molar ratios of the respective components in step 1,among other variables. However, the polythiol composition often can beformed over a time period in step 2 that can be in a range from 1 minuteto 8 hours, such as, for example, from 2 minutes to 6 hours, from 5minutes to 5 hours, from 10 minutes to 4 hours, or from 15 minutes to 3hours.

In embodiments of this invention, once the limonene, H₂S, and thephosphite compound (if used) are contacted, the polythiol compositioncan be formed in the presence of electromagnetic radiation. Forinstance, the polythiol composition can be formed in the presence ofultraviolet light. Additionally or alternatively, the polythiolcomposition can be formed by light photolysis initiation of a freeradical initiator. Additionally or alternatively, the polythiolcomposition can be formed under conditions suitable for the thermaldecomposition of a free radical initiator. Additionally, aphotoinitiator can be utilized in conjunction with ultraviolet light orlight photolysis initiation of a free radical initiator. Free radicals,therefore, can be generated in situ by a suitable energy source, or canbe generated by the thermal decomposition of a free radical initiator,or by a combination of these sources. The polythiol composition can beformed in the presence of free radicals from any one of aforementionedsources, including combinations thereof, but is not limited to freeradicals generated only by these means.

In an embodiment, the step 1 contacting of the limonene, H₂S, and thephosphite compound (if used) can be conducted prior to the generation offree radicals and the formation of the polythiol composition in step 2.

When the polythiol composition is formed in the presence of ultravioletlight, ultraviolet light in the range, for example, from 172 to 450 nm,from 172 to 380 nm, or from 172 to 320 nm, can be employed. Ultravioletlight can be supplied from ultraviolet lamps, but other sources ofultraviolet light can be employed, and are to be considered within thescope of the present invention.

The free radical initiator can be any free radical initiator capable offorming free radicals under thermal decomposition or light photolysis.For example, the free radical initiator employed for the formation ofthe polythiol composition can comprise a —N═N— group, a —O—O— group, orcombinations thereof; alternatively, a —N═N— group; or alternatively, a—O—O— group. Free radical initiators, therefore, can include, but arenot limited to, peroxy compounds, organic azo compounds, or combinationsthereof; alternatively, peroxy compounds; or alternatively, organic azocompounds. Peroxy compounds which can be utilized can include peroxides,hydroperoxides, peroxyesters, diacylperoxides, and percarbonates;alternatively, peroxides; alternatively, hydroperoxides; alternatively,peroxyesters; alternatively, diacylperoxides; or alternatively,percarbonates. In an embodiment, the peroxide can be a dialkyl peroxide.In an embodiment, the hydroperoxide can be an alkyl hydroperoxide. In anembodiment, the peroxy ester can be an alkyl peroxyalkanoate, oralternatively, an alkyl peroxyarenoate. In an embodiment, thediacylperoxide can be a diaroyl peroxide, or alternatively, a diakoylperoxide. In an embodiment, the percarbonate can be a dihydrocarbylpercarbonate; alternatively, a diarylpercarbonate; or alternatively, adialkylpercarbonate. Generally, the hydrocarbon and/or alkane group(s)utilized in any peroxy compound can be a C₁ to C₃₀, C₂ to C₁₈, C₂ toC₁₀, or C₂ to C₅ hydrocarbon and/or alkane group(s). Generally, thearene group utilized in any peroxy compound can be a C₆ to C₃₀, C₆ toC₁₈, C₆ to C₁₅, or C₆ to C₁₀ arene group(s). Illustrative non-limitingexamples of peroxy compounds which can be utilized can include, but arenot limited to, diisobutyryl peroxide,1-(2-ethylhexanoylperoxy)-1,3-dimethylbutyl peroxypivalate,cumylperoxyneodecanoate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate,t-butyl peroxyneodecanoate, 1,1,3,3-tetramethylbutyl peroxypivalate,t-butyl peroxyneoheptanoate, t-amyl peroxypivalate, t-butylperoxypivalate, di(3,5,5-trimethylhexanoyl) peroxide, dilauroylperoxide, didecanoyl peroxide,2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane,1,1,3,3-tetramethylbutyl peroxy 2-ethylhexanoate, t-amyl peroxy2-ethylhexanoate, dibenzoyl peroxide, acetyl peroxide t-butyl peroxy2-ethylhexanoate, t-butyl peroctanoate, t-butyl peroxydiethylacetate,t-butyl peroxyisobutyrate, t-butyl peroxy 3,5,5-trimethylhexanoate,t-butyl peroxyacetate, t-butyl peoxybenzoate, 2,4-dichlorobenzoylperoxide, t-butylpermaleic acid, di-t-butyl diperphthalate,di(4-t-butylcyclohexyl) peroxydicarbonate, di(2-ethylhexyl)peroxydicarbonate, dibutyl peroxydicarbonate, dicetyl peroxydicarbonate,dimyristyl peroxydicarbonate, t-amylperoxy 2-ethylhexyl carbonate,t-butylperoxy isopropyl carbonate, t-butylperoxy 2-ethylhexyl carbonate,1,1-di(t-butylperoxy) 3,5,5-trimethylcyclohexane,2,2-di(4,4-di(t-butylperoxy)cyclohexyl)propane,1,1-di(t-butylperoxy)cyclohexane, 2,2-di(t-butylperoxy)butane,di(t-amyl)peroxide, dicumyl peroxide, di(t-butylperoxyisopropyl)benzene,2,5-dimethyl-2,5-di(t-butylperoxy)hexane, t-butyl cumyl peroxide,2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, di-t-butyl peroxide,3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxoane, t-butylhydroperoxide, methyl benzyl hydroperoxide, octylperbenzoate, methylethyl ketone peroxide, acetone peroxide, or combinations thereof.

Non-limiting examples of suitable azo compounds include α,α′-azodiisobutyronitrile (AIBN), azobenzene, azomethane,2,2′-azodi(2-methylbutyronitrile), 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile), dimethyl 2,2′-azobis(2-methylpropionate),1,1′-azobis(cyclohexane-1-carbonitrile), 1-[(cyano-1-methylethyl)azo]formamide, 2,2′-azobis(N-cyclohexyl-2-methylpropionamide),2,2′-azobis(2,4-dimethyl valeronitrile),2,2′-azobis(-methylbutyronitrile),2,2′-azobis[N-(2-propenyl)-2-methylpropionamide],2,2′-azobis(N-butyl-2-methylpropionamide), 2,2′-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl] propionamide,2,2′-azobis[2-methyl-N-(2-hydroxyethyl)propionamide],2,2′-azobis[2-(2-imidazolin-2-yl)propane],2,2′-azobis{2-methyl-N-[2-(1-hydroxybutyl)] propionamide},2,2′-azobis(2-methylpropionitrile), 4,4′-azobis(4-cyanovaleric acid),2,2′-azobis(2-methylpropane),2,2′-azobis(2-methylpropionamidine)dihydrochloride, methylpropionitrile,azodicarboxamide, or combinations thereof.

Generally, the peroxide and azo compound free radical initiators thatcan be utilized in accordance with the present invention decompose underfirst order kinetics. Skilled artisans can readily find the first orderkinetic parameters which can be utilized to describe the decompositionof a particular free radical catalyst from sources such as chemicalsuppliers, industry reference publications, and/or open literaturepublications. Under first order kinetics, the time required for a givenfraction (or percentage) of the free radical initiator to decompose, ata specific temperature, into initiating species is independent of theconcentration of the free radical. This phenomenon is often stated as ahalf-life; that is, the time in which one-half of the free radicalinitiator decomposes under specific conditions (e.g., temperature).According to the first order kinetics, the half-life of a free radicalinitiator is defined as the time it takes one-half of the initiator todecompose at a particular temperature. Using the available first orderkinetic parameters for a particular free radical initiator, theconcentration of the free radical initiator present in the reactionmixture can be determined at a particular time during the reaction basedupon the knowledge of the amount of free radical initiator added to thereaction, the times at which additional (if any) free radical initiatoris added to the reaction, and the temperature profile of the reaction.

When the polythiol composition is formed under conditions utilizing thethermal decomposition of a free radical initiator, the polythiolcomposition can be formed at a temperature within a temperature range ofthe 1 hour half-life of the free radical initiator. Alternatively, whenthe polythiol composition is formed under conditions utilizing thethermal decomposition of a free radical initiator, the polythiolcomposition can be formed using a free radical initiator having ahalf-life within a time range at the temperature utilized to form thepolythiol composition. For example, step 2 of the process (the formationof the polythiol composition) can be conducted at a temperature within±25° C. of the 1 hour half-life of the free radical initiator. In otherembodiments, the polythiol composition can be formed at a temperaturewithin ±20° C. of the 1 hour half-life of the free radical initiator;alternatively, at a temperature within ±15° C. of the 1 hour half-lifeof the free radical initiator; alternatively, at a temperature within±10° C. of the 1 hour half-life of the free radical initiator. Inanother embodiment, the polythiol composition can be formed using a freeradical initiator having a half-life within a range from 0.1 to 10 hoursat the temperature the polythiol composition is formed (i.e., in step 2of the process). Alternatively, the polythiol composition can be formedusing a free radical initiator having a half-life ranging from 0.1 to 10hours, from 0.25 to 4 hours, or from 0.5 to 2 hours, at the temperaturethe polythiol composition is formed. As above, in some embodiments ofthis invention, the polythiol composition can be formed at a temperaturein a range from −30° C. to 150° C.; alternatively, from −20° C. to 130°C.; alternatively, from −10° C. to 100° C.; alternatively, from −5° C.to 80° C.; alternatively, from 0° C. to 60° C.; or alternatively, from10° C. to 45° C.

Depending upon the particular free radical initiator, a free radicalinitiator can produce a different number of free radicalreaction-initiating species per mole of free radical initiator; thus,the concentration of the free radical initiator can be stated in termswhich describe the number of free radical reaction-initiating speciesgenerated per mole of free radical initiator. The term “equivalent” isoften used to describe the number of reaction-initiating speciesproduced per mole of free radical initiator. For example, one skilled inthe art will readily recognize that di-t-butylperoxide can generate twofree radical reaction-initiating species per mole of di-t-butylperoxide,while 2,5-bis(t-butylperoxy)-2,5-dimethylhexane can generate four freeradical reaction-initiating species per mole of2,5-bis(t-butylperoxy)-2,5-dimethylhexane.

In some embodiments, a photoinitiator can be utilized. Commerciallyavailable photoinitiators include, by way of example, Irgacure® 184(1-hydroxy-cyclohexyl-phenyl-ketone), Irgacure® 500 (50%1-hydroxy-cyclohexyl-phenyl-ketone and 50% benzophenone), Irgacure® 819(Bis-(2,4,6-trimethylbenzoyl)-phenylphosphineoxide), and Irgacure® 127(2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methyl-propan-1-one),all available from Ciba Specialty Chemicals, and Duracure 1173(2-hydroxy-2-methyl-1-phenyl-1-propanone).

When a free radical initiator is present in step 1 and/or in step 2 ofthe process, the weight percentage of the free radical initiator, basedon the weight of the limonene, can be in a range from 0.05 to 10 wt. %,from 0.1 to 9 wt. %, from 0.2 to 5 wt. %, or from 0.1 to 2 wt. %. When aphotoinitiator is present in step 1 and/or in step 2 of the process, theweight percentage of the photoinitiator, based on the weight of thelimonene, can be less than or equal to 5 wt. %, less than or equal to 3wt. %, less than or equal to 2 wt. %, or less than or equal to 1.5 wt.%, and typical non-limiting ranges can include from 0.01 to 5 wt. %,from 0.05 to 5 wt. %, from 0.5 to 3 wt. %, or from 1 to 4 wt. %. Otheramounts of the free radical initiator and/or the photoinitiator can beemployed depending on the specific process conditions used to form thepolythiol composition (e.g., temperature, pressure, time) and therespective ratios of H₂S to limonene and of phosphite compound tolimonene, amongst other factors. It is contemplated that more than onefree radical initiator, more than one photoinitiator, or combinations offree radical initiator(s) and photoinitiator(s), can be employed.

In an embodiment, the polythiol composition can be formed in the absenceof a solvent. However, in other embodiments, the polythiol can be formedin the presence of a solvent. Typically, when used, the solvent can bepresent in an amount up to 1,000 wt. %, based on the weight of thelimonene. Alternatively, the formation of the polythiol can be performedin the presence of a solvent in an amount up to 750 wt. %, up to 500 wt.%, up to 250 wt. %, up to 200 wt. %, up to 150 wt. %, or up to 100 wt.%. When a solvent is utilized, the minimum amount of solvent utilizedcan be at least 5 wt. %, at least 10 wt. %, at least 25 wt. %, at least50 wt. %, or at least 75 wt. %, based on the weight of the limonene.Generally, the amount of solvent which can be utilized can range fromany minimum amount of solvent disclosed herein to any maximum amount ofsolvent disclosed herein. In some non-limiting embodiments, theformation of the polythiol can be performed in the presence of a solventin an amount of from 5 wt. % to 1,000 wt. %, from 10 wt. % to 750 wt. %,from 25 wt. % to 500 wt. %, from 50 wt. % to 250 wt. %, from 50 wt. % to150 wt. %, or from 75 wt. % to 125 wt. %, based on the weight of thelimonene. The solvent can be contacted with the limonene, H₂S, and thephosphite compound (if used) in step 1 of the process, and remainpresent during the formation of the polythiol composition.Alternatively, the solvent can be added after the initial contacting instep 1. Solvents which can be utilized as the solvent are describedherein, and these solvents can be utilized without limitation in theprocesses described herein.

In the processes for producing a polythiol composition disclosed herein,it is contemplated that at least 60% of the carbon-carbon double bondsof the limonene can react to form a sulfur-containing group in thepolythiol composition. Often, at least 65% of the carbon-carbon doublebonds of the limonene can react to form a sulfur-containing group;alternatively, at least 70%; alternatively; at least 75%; alternatively,at least 80%; alternatively, at least 85%; alternatively, at least 90%;alternatively, at least 95%; alternatively, at least 98%; oralternatively, at least 99%.

Once formed, the polythiol composition, or specific fractions of thepolythiol composition, can be purified and/or isolated and/or separatedusing suitable techniques which include, but are not limited to,evaporation, distillation, crystallization, extraction, washing,decanting, filtering, drying, including combinations of more than one ofthese techniques. In one embodiment, the process for producing apolythiol composition can further comprise a step of separating orremoving at least a portion of the H₂S, of the phosphite compound (ifused), of the limonene, of compounds having only one sulfur atom(monosulfur compounds), or any combination thereof, from the polythiolcomposition. For instance, these materials can be separated or removedby distillation, by short path distillation, by wiped film evaporation,or by a combination of these techniques.

Consistent with embodiments of this invention, these processes forproducing polythiol compositions can be used to produce any of thepolythiol compositions disclosed herein.

Phosphite Compounds

Generally, the phosphite compound employed in certain processes forforming a polythiol composition disclosed herein can comprise, consistessentially of, or consist of, a compound having the formula:P(OR¹)₃.In this formula, each R¹ independently can be a C₁-C₁₈ hydrocarbylgroup; alternatively, a C₁-C₁₀ hydrocarbyl group; alternatively, a C₁-C₅hydrocarbyl group; alternatively, a C₁-C₁₈ alkyl group; alternatively, aC₁-C₁₀ alkyl group; alternatively, a C₁-C₅ alkyl group; alternatively, aC₆-C₁₈ aryl group; or alternatively, a C₆-C₁₀ aryl group. Accordingly,each R¹ independently can be a methyl group, an ethyl group, a propylgroup, a butyl group, a pentyl group, a hexyl group, a heptyl group, anoctyl group, a nonyl group, or a decyl group; alternatively, R¹ can be amethyl group, an ethyl group, a propyl group, a butyl group, or a pentylgroup; alternatively, R¹ can be a methyl group; alternatively, R¹ can bean ethyl group; alternatively, R¹ can be a propyl group; alternatively,R¹ can be a butyl group; alternatively, R¹ can be a pentyl group;alternatively, R¹ can be a hexyl group; alternatively, R¹ can be aheptyl group; alternatively, R¹ can be an octyl group; alternatively, R¹can be a nonyl group; or alternatively, R¹ can be a decyl group. In someembodiments, each R¹ independently can be a phenyl group, a tolyl group,a xylyl group, or a naphthyl group; alternatively, a phenyl group, atolyl group, or a xylyl group; alternatively, a phenyl group;alternatively, a tolyl group; alternatively, a xylyl group; oralternatively, a naphthyl group.

In accordance with an embodiment of this invention, the phosphitecompound can comprise, consist essentially of, or consist of, atrialkylphosphite, or alternatively, a triarylphosphite. In accordancewith another embodiment of this invention, the phosphite compound cancomprise, consist essentially of, or consist of, trimethylphosphite,triethylphosphite, tributylphosphite, or combinations thereof. Yet, inaccordance with another embodiment of this invention, the phosphitecompound can comprise trimethylphosphite; alternatively,triethylphosphite; or alternatively, tributylphosphite. In anotherembodiment, the phosphite compound can comprise, consist essentially of,or consist of, triphenylphosphite.

Solvents

As described herein, the polythiol composition can be formed in thepresence of a solvent. The solvent can comprise, consist essentially of,or consist of, a hydrocarbon, an aromatic hydrocarbon, a ketone, analcohol, an ether, or combinations thereof. Hence, mixtures and/orcombinations of solvents can be utilized in the processes of formingpolythiol compositions disclosed herein.

In an embodiment, the solvent employed in forming the polythiolcomposition can comprise, consist essentially of, or consist of, ahydrocarbon solvent. Suitable hydrocarbon solvents can include, forexample, aliphatic hydrocarbons, petroleum distillates, or combinationsthereof. Aliphatic hydrocarbons which can be useful as the solventinclude C₃ to C₂₀ aliphatic hydrocarbons; alternatively, C₄ to C₁₅aliphatic hydrocarbons; or alternatively, C₅ to C₁₀ aliphatichydrocarbons. The aliphatic hydrocarbons can be cyclic or acyclic,and/or can be linear or branched, unless otherwise specified.

Non-limiting examples of suitable acyclic aliphatic hydrocarbon solventsthat can be utilized singly or in any combination include pentane(n-pentane or a mixture of linear and branched C₅ acyclic aliphatichydrocarbons), hexane (n-hexane or a mixture of linear and branched C₆acyclic aliphatic hydrocarbons), heptane (n-heptane or a mixture oflinear and branched C₇ acyclic aliphatic hydrocarbons), octane (n-octaneor a mixture of linear and branched C₈ acyclic aliphatic hydrocarbons),decane (n-decane or a mixture of linear and branched C₁₀ acyclicaliphatic hydrocarbons), and combinations thereof; alternatively,pentane (n-pentane or a mixture of linear and branched C₅ acyclicaliphatic hydrocarbons), hexane (n-hexane or a mixture of linear andbranched C₆ acyclic aliphatic hydrocarbons), heptane (n-heptane or amixture of linear and branched C₇ acyclic aliphatic hydrocarbons),octane (n-octane or a mixture of linear and branched C₈ acyclicaliphatic hydrocarbons), and combinations thereof; alternatively, hexane(n-hexane or a mixture of linear and branched C₆ acyclic aliphatichydrocarbons), heptane (n-heptane or a mixture of linear and branched C₇acyclic aliphatic hydrocarbons), octane (n-octane or a mixture of linearand branched C₈ acyclic aliphatic hydrocarbons), and combinationsthereof; alternatively, pentane (n-pentane or a mixture of linear andbranched C₅ acyclic aliphatic hydrocarbons); alternatively, hexane(n-hexane or a mixture of linear and branched C₆ acyclic aliphatichydrocarbons); alternatively, heptane (n-heptane or a mixture of linearand branched C₇ acyclic aliphatic hydrocarbons); or alternatively,octane (n-octane or a mixture of linear and branched C₈ acyclicaliphatic hydrocarbons).

In an embodiment, the solvent employed in forming the polythiolcomposition can comprise, consist essentially of, or consist of, anaromatic hydrocarbon solvent. Aromatic hydrocarbons can include C₆ toC₃₀ aromatic hydrocarbons; alternatively, C₆ to C₂₀ aromatichydrocarbons; or alternatively, C₆ to C₁₀ aromatic hydrocarbons.Non-limiting examples of suitable aromatic hydrocarbons that can beutilized singly or in any combination include benzene, toluene, xylene(including ortho-xylene, meta-xylene, para-xylene, or mixtures thereof),and ethylbenzene, or combinations thereof; alternatively, benzene;alternatively, toluene; alternatively, xylene (including ortho-xylene,meta-xylene, para-xylene or mixtures thereof); or alternatively,ethylbenzene.

In an embodiment, the solvent employed in forming the polythiolcomposition can comprise, consist essentially of, or consist of, aketone solvent, an alcohol solvent, an ether solvent, or combinationsthereof; alternatively, a ketone solvent; alternatively, an alcoholsolvent; or alternatively, an ether solvent. Suitable ketones, alcohols,or ethers include C₂ to C₂₀ ketones, alcohols, or ethers; alternatively,C₂ to C₁₀ ketones, alcohols, or ethers; or alternatively, C₂ to C₅ketones, alcohols, or ethers. Non-limiting examples of suitable ketonesolvents can include acetone, ethyl methyl ketone, and combinationsthereof. Non-limiting examples of suitable alcohol solvents can includemethanol, ethanol, propanol, isopropanol, n-butanol, isobutanol,pentanol, hexanol, heptanol, octanol, benzyl alcohol, phenol,cyclohexanol, or combinations thereof. Suitable ether solvents can becyclic or acyclic, non-limiting examples of which can include dimethylether, diethyl ether, methyl ethyl ether, monoethers or diethers ofglycols (e.g., dimethyl glycol ether), furans, substituted furans,dihydrofuran, substituted dihydrofurans, tetrahydrofuran (THF),substituted tetrahydrofurans, tetrahydropyrans, substitutedtetrahydropyrans, 1,3-dioxanes, substituted 1,3-dioxanes, 1,4-dioxanes,substituted 1,4-dioxanes, or mixtures thereof. In an embodiment, eachsubstituent of a substituted furan, substituted dihydrofuran,substituted tetrahydrofuran, substituted tetrahydropyran, substituted1,3-dioxane, or substituted 1,4-dioxane, can be a C₁ to C₅ alkyl group.

Mining Chemical Collectors

Embodiments of this invention also are directed to collectorcompositions (such as mining chemical collector compositions) thatcomprise any of the polythiol compositions disclosed herein.Unexpectedly, it was found that the polythiol compositions disclosedherein are very effective at removing certain desirable metals frommining ores.

In one embodiment, a collector composition of this invention cancomprise water and any of the polythiol compositions disclosed herein.Often, the amount of water in the collector composition can be greaterthan 75 wt. %, greater than 95 wt. %, or greater than 99 wt. %, andtypical non-limiting ranges include from 75 to 99.99 wt. %, from 95 to99.99 wt. %, or from 99 to 99.99 wt. % water, based on the total weightof the collector composition. The amount of the polythiol compositionpresent in the collector composition typically can be less than 0.1 wt.%, less than 0.01 wt. %, or less than 0.001 wt. %.

In another embodiment, the collector composition of this invention cancomprise any of the polythiol compositions disclosed herein and asuitable pH control agent. Illustrative pH control agents can include,but are not limited to, lime, carbonate compounds, and the like, as wellas combinations thereof. In yet another embodiment, the collectorcomposition can comprise any of the polythiol compositions disclosedherein and a suitable frothing agent. Illustrative frothing agents caninclude, but are not limited to, pine oil; alcohols such as methylisobutyl carbinol (MIBC); and polyether alcohols such as NALFLOTE® 9837and Cytec OREPREP® X-133. Combinations of more than one frothing agentcan be used. In still another embodiment, the collector composition cancomprise any of the polythiol compositions disclosed herein, a frothingagent, a pH control agent, and water.

Collector compositions consistent with this invention can comprise apolythiol composition and can contain other components—such as frothingagents, pH control agents, water, and others—and these compositions canbe contacted with an ore, as described further hereinbelow. Any suitableorder of contacting any components of the collector composition with theore can be used; and such collector compositions, whether solutions,slurries, blends, immiscible mixtures (e.g., in some instances, thepolythiol composition is not soluble/miscible in water), and so forth,are encompassed herein. For instance, a ground ore can be contactedwith, in any order, a polythiol composition, a frothing agent, a pHcontrol agent, and a first amount of water (which can be relativelysmall), resulting in a slurry of the ore and a collector compositioncomprising the polythiol composition, the frothing agent, the pH controlagent, and water. In some embodiments, a second amount of water (whichcan be relatively large) can be added to this slurry prior to theflotation process, resulting in a slurry of the ore in a collectorcomposition comprising lower concentrations of the polythiolcomposition, the frothing agent, and the pH control agent. Othersuitable methods and orders of forming the collector compositions,whether in the presence of the ore or not, would be readily recognizedby those of skill in the art, and such are encompassed herein.

Moreover, the polythiol compositions disclosed herein can be used aloneor in combination with other suitable (second) collector agents. Thus,any of the collector compositions can further comprise a secondcollector agent, non-limiting examples of which can include a xanthate,a xanthic ester, a thionocarbonate, a dialkyl dithiophosphate, and thelike, as well as combinations thereof.

Also provided herein are flotation processes for the recovery of metalsfrom ores. The metal can be recovered in any form, for instance, ametal-containing compound (e.g., copper sulfides, molybdenum sulfides),a metal ion, or elemental metal, as well as combinations thereof. Onesuch flotation process for the recovery of a metal from an ore cancomprise contacting the ore with any of the collector compositionsdisclosed herein (or any of the polythiol compositions disclosedherein). Equipment and techniques for the flotation recovery of variousmetals from mining ores are well known to those of skill in the art, andare illustrated representatively herein in the examples that follow.

Generally, the metal recovered from the ore comprises a transitionmetal, one or more Group 3-12 metals. In some embodiments, the metal cancomprise a Group 3-11 transition metal, or a Group 5-12 transitionmetal, while in other embodiments, the metal can comprise gold, silver,platinum, copper, nickel, iron, lead, zinc, molybdenum, cobalt, orchromium, as well as combinations thereof. In particular embodiments ofthis invention, the metal can comprise copper and molybdenum;alternatively, copper; or alternatively, molybdenum. In addition, othertransition metals, such as iron, can be recovered along with copperand/or molybdenum.

The flotation processes and mining chemical collector compositionsdescribed herein are not limited to any particular ore. However, theeffectiveness of such processes and compositions are particularlybeneficial when the ore comprises a copper-bearing ore, amolybdenum-bearing ore, or a copper-bearing and molybdenum-bearing ore.Illustrative and non-limiting examples of such ores includechalcopyrite, chalcocite, and the like.

Any suitable amount of the collector composition and/or the polythiolcomposition can be used in the flotation recovery processes. Often, butnot limited thereto, the polythiol composition and the ore are contactedat a weight ratio in a range from about 0.001 lb of the polythiolcomposition per ton of ore to about 5 lb of the polythiol compositionper ton of ore, or from about 0.01 lb of the polythiol composition perton of ore to about 1 lb of the polythiol composition per ton of ore.

Unexpectedly, the polythiol compositions disclosed herein, and anyresultant collector compositions containing the polythiol compositions,have high recovery rates of certain transition metals. For example, the% recovery of copper in the flotation process can be at least about 75wt. %, at least about 80 wt. %, at least about 85 wt. %, or at leastabout 90 wt. %, and often as high as 95-98 wt. %. Similarly, the %recovery of molybdenum in the flotation process can be at least about 60wt. %, at least about 65 wt. %, at least about 80 wt. %, at least about85 wt. %, or at least about 90 wt. %, and often as high as 92-97 wt. %.

Furthermore and surprisingly, in some embodiments, the % recovery ofcopper, the % recovery of molybdenum, or the % recovery of copper andmolybdenum, can be greater than that of a mine standard, under the sameflotation conditions. As would be recognized by those of skill in theart, a mine standard is the prevailing collector composition currentlybeing used for a given ore and/or desired transition metal. Minestandards are discussed in greater detail in the examples that follow.In some embodiments, the % recovery of copper, the % recovery ofmolybdenum, or the % recovery of copper and molybdenum, can be withinabout 5 wt. %, within about 3 wt. %, within about 2 wt. %, or withinabout 1 wt. %, of the mine standard, under the same flotationconditions.

Additionally or alternatively, the % recovery of copper, the % recoveryof molybdenum, or the % recovery of copper and molybdenum, can begreater than that of a mining collector composition containing TDDM(tertiary dodecyl mercaptan) or NDDM (n-dodecyl mercaptan), under thesame flotation conditions. Thus, in some instances, the polythiolcompositions disclosed herein are superior to TDDM and/or NDDM. In otherembodiments, the % recovery of copper, the % recovery of molybdenum, orthe % recovery of copper and molybdenum, can be within about 5 wt. %,within about 3 wt. %, within about 2 wt. %, or within about 1 wt. %, ofthat achieved with TDDM and/or that achieved with NDDM, under the sameflotation conditions.

EXAMPLES

The invention is further illustrated by the following examples, whichare not to be construed in any way as imposing limitations to the scopeof this invention. Various other aspects, embodiments, modifications,and equivalents thereof which, after reading the description herein, maysuggest themselves to one of ordinary skill in the art without departingfrom the spirit of the present invention or the scope of the appendedclaims.

Product composition information based upon GC-FID data is presented inarea percentages, unless otherwise specified. GC-FID analysis wasperformed on an Agilent® 7890 gas chromatograph using a 2 m×0.25 mm×1.0μm film DB-1 capillary column with Flame Ionization Detector usinghelium as the carrier gas. A sample of the product composition wasdissolved in acetone at a 3:1 acetone to product sample ratio and 0.4 μLof the diluted sample product was injected into a split/splitless PVTinlet. The GC inlet parameters were an inlet temperature of 275° C., aninitial inlet pressure of 2.4 psi, a final inlet pressure of 5.2 psi,constant flow conditions of 2 mL/minute of helium, and an inlet splitratio of 50:1. The temperature program for the GC-FID analysis was aninitial temperature of 70° C. for 2 minutes, followed by a temperatureramp of 8° C./minute to 200° C., followed by a temperature ramp of 15°C./minute to 300° C. and a temperature hold at 300° C. for 10 minutes.The GC-FID detector was operated at a temperature of 300° C. having ahydrogen gas flow of 25 mL/minute, an air flow of 300 mL/minute, and amakeup helium gas flow of 25 mL/minute. GC-FID analysis data wasacquired with Agilent Chemstation®.

Weight percentage of thiol sulfur (wt. % SH) was determined by iodinetitration, and weight percentage of total sulfur (wt. % Total S) wasdetermined by x-ray analysis. Mercaptan equivalent weight (SHEW) isequal to the average molecular weight (g/mol) of the mercaptan dividedby the number of SH functionality present in the mercaptan molecule, andcan be calculated as follows: SHEW=(32.06 grams mercaptansulfur/equivalent)/(wt. % SH/100), where wt. % SH=grams thiol sulfur (ormercaptan sulfur) per gram of the polythiol composition.

Raman spectroscopy was performed with a Kaiser Optical System R_(XN)2spectrometer and by observing certain wavenumber ranges for olefinconversion, such as vinylidene olefin at 1644 cm⁻¹ and cyclohexene ringolefin at 1676 cm⁻¹.

Samples were analyzed for molybdenum content by digesting an ore sampleover heat in a solution containing potassium chlorate, nitric acid, andhydrochloric acid. After the digested sample was cooled, super floc wasadded, and the sample was analyzed via atomic absorption using a nitrousoxide-acetylene red flame. Standards ranged from 50-100 ppm by weightmolybdenum. A similar procedure with the necessary modifications wasused to analyze for copper and iron content.

Table I summarizes calculated product characteristics for polythiolcompounds derived from limonene. In Table I, N is the number ofsubstituted cyclohexyl moieties, —SH is the number of thiol groups, —S—is the number of sulfide groups, Total S is the total number of sulfurs,MW is the molecular weight of the polythiol compound (g/mol), % SH isthe wt. % thiol sulfur, % Sulfide is the wt. % sulfide sulfur, % Total Sis the wt. % sulfur, Ratio SH/S is the ratio of thiol sulfur to sulfidesulfur, and SHEW is the mercaptan equivalent weight.

Table II summarizes calculated product characteristics for illustrativepolythiol compositions derived from limonene. In Table II, N is thenumber of substituted cyclohexyl moieties, % SH is the wt. % thiolsulfur of the composition, % Sulfide is the wt. % sulfide sulfur of thecomposition, % Total S is the wt. % sulfur of the composition, RatioSH/S is the ratio of thiol sulfur to sulfide sulfur of the composition,and SHEW is the mercaptan equivalent weight of the composition. Thefirst entry is high purity dipentene dimercaptans, while the othercompositions illustrate the impact of intermolecular sulfide compounds(heavies, N=2 and above) on the product features of the polythiolcompositions.

Examples 1-8 Polythiol Compositions Produced from Limonene

A 1.5-L ultraviolet light reactor was used for Examples 1-8; the workingvolume was 1.2 L. The stainless-steel reactor had a quartz lamp wellmounted horizontal to an off-set stir shaft. The reactor was equippedwith a thermowell, cooling coils, a charge port, a sample port, and abottom drain valve. To the 1.5-L reactor, the limonene, the phosphitecompound (triethylphosphite (TEP), if used), and the photoinitiator(Irgacure 500, if used) were charged to the reactor through the chargeport. The reactor was sealed and pressure checked with nitrogen at 450psig. The reactor was vented and the desired amount of H₂S was chargedto the reactor. The reactor contents were heated and controlled bysetting the external circulating bath at the desired temperature ofabout 25-30° C. for UV-initiated Examples 1 to 8. The operating pressureranged from about 300 to 450 psig.

The reaction mixture was allowed to mix for 15 to 30 minutes. After thismixing period, the ultraviolet lamp was turned on, and the olefinconversion to a sulfur-containing group was monitored by observingolefin peaks using Raman Spectroscopy. The ultraviolet lamp typicallyrequired 3-5 minutes to reach full power. The ultraviolet lamp power was100 watts.

When the conversion of carbon-carbon double bonds was complete or thedesired reaction time was reached, the ultraviolet lamp was turned off.The H₂S was then slowly vented from the reactor. The reaction productwas placed in a rotoevaporator at 60° C. and low vacuum to removeadditional residual H₂S. The crude polythiol compositions of Examples1-8 were analyzed using gas chromatography (GC) and data presented inarea percentages, unless otherwise specified. GC analysis of thesulfur-containing compounds excluded peaks attributed tophosphorus-containing materials.

Table III summarizes certain process conditions and analytical resultsfor the polythiol compositions of Examples 1-8. In Table III, theH₂S:olefin molar ratio was 15:1, the time (minutes) was the total timein the reactor, the % conversion (Raman) was the conversion of olefingroups to sulfur-containing groups. For the GC analysis (area %), enewas the amount of compounds with residual olefin (e.g., dipentene,mono-ene impurities), mono-S was the amount of compounds with only onesulfur, DPDM was the amount of dipentene dimercaptan compounds, andheavies was the amount of compounds with at least one thiol sulfur(typically, two) and at least one sulfide sulfur group. The limonenesource for Examples 1-2 was a food-grade limonene from Treatt. Thelimonene source for Examples 3-8 was from Orange Terpenes, either lot 1or lot 2. No noticeable difference between limonene starting materialswas noted.

The results from Table III indicate that without the phosphite compound,the conversion of limonene was low and the reaction time was long. Whenboth phosphite and photoinitiator were used, the reaction time was 15-20minutes with acceptable conversion. Examples 1-8 produced polythiolcompositions containing about 72-90% DPDM and about 4-8% heavies.

Examples 9-16 Polythiol Compositions Produced from Limonene

A 5-L ultraviolet light reactor was used for Examples 9-16; the workingvolume was 4 L. The stainless-steel reactor had a quartz lamp wellmounted horizontal to an off-set stir shaft. The reactor was equippedwith a thermowell, cooling coils, a charge port, a sample port, and abottom drain valve. To the 5-L reactor, the limonene, the phosphitecompound (tributylphosphite (TBP), if used), and the photoinitiator(Irgacure 500, if used) were charged to the reactor through the chargeport. The reactor was sealed and pressure checked with nitrogen at 450psig. The reactor was vented and the desired amount of H₂S was chargedto the reactor. The reactor contents were heated and controlled bysetting the external circulating bath at the desired temperature ofabout 25-30° C. for UV-initiated Examples 9-16. The reaction pressurewas 300-450 psig.

The reaction mixture was allowed to mix for 15 to 30 minutes. After thismixing period, the ultraviolet lamp was turned on, and the olefinconversion to a sulfur-containing group was monitored by observingolefin peaks using Raman Spectroscopy. The ultraviolet lamp typicallyrequired 3-5 minutes to reach full power. The ultraviolet lamp power was100 watts.

When the conversion of carbon-carbon double bonds was complete or thedesired reaction time was reached, the ultraviolet lamp was turned off.The H₂S was then slowly vented from the reactor. The reaction productwas placed in a rotoevaporator at 60° C. and low vacuum to removeadditional residual H₂S. The crude polythiol compositions of Examples9-16 were analyzed using gas chromatography (GC) and data presented inarea percentages, unless otherwise specified. GC analysis of thesulfur-containing compounds excluded peaks attributed tophosphorus-containing materials.

Table IV summarizes certain process conditions and analytical resultsfor the polythiol compositions of Examples 9-16. Table IV indicates thatexcellent conversion was achieved when either sufficient amounts of thephosphite compound were used, or both phosphite and photoinitiator wereused. Examples 9-16 produced polythiol compositions containing about76-90% DPDM and about 5-9% heavies, and characterized by about 28-31 wt.% total sulfur.

Examples 17-24 Polythiol Compositions Produced from Limonene

Examples 17-24 were performed in substantially the same manner as thatof Examples 9-16. Table V summarizes certain process conditions andanalytical results for the polythiol compositions of Examples 17-24.Some of the experiments from Examples 9-16 and Table IV are also listedin Table V and renumbered for ease of comparison. Examples 17-24produced polythiol compositions containing about 76-90% DPDM and about5-10% heavies, and characterized by about 28-30 wt. % total sulfur.

Examples 25-29 Polythiol Compositions Produced from Limonene Before andafter Distillation

A 379-L (100-gallon) ultraviolet light reactor was used for Examples25-29; working volume was 80 gallons. The 379-L reactor had a vesselwith an internal heating/cooling coil, a quartz lamp and lamp wellmounted vertically in an external pipe, and a pump to circulate thefluid the contents from the vessel, into and through the pipe, and backto the vessel. To the vessel, the limonene (28.4 kg) and the phosphitecompound (if used, 140 g) were charged to the vessel and then H₂S (212.5kg) was added. The pump was turned on, and the reactor contents weremixed and circulated for about 15 minutes. After this mixing period, theultraviolet lamp was turned on, and the olefin conversion to asulfur-containing group was monitored by observing olefin peaks usingRaman spectroscopy. The ultraviolet lamp typically required 3-5 minutesto reach full power. The ultraviolet lamp power was 2.5-7.5 kW. Thereaction temperature was in the 25-30° C. range for UV-initiatedExamples 25A-27A, and the operating pressure was in the 260-430 psigrange. The lamp power was varied to settings of 2.5 kW, 5 kW, or 7.5 kWduring the run to maintain acceptable reactor pressures. For a 30-minuteperiod in the middle of Example 25, the lamp was turned off.

When the conversion of carbon-carbon double bonds was complete or thedesired reaction time was reached, the ultraviolet lamp was turned off.The H₂S was then slowly and safely vented from the reactor. The reactionproduct was placed in a rotoevaporator at 60° C. and low vacuum tosafely remove additional residual H₂S. The crude polythiol compositionsof Examples 25A-27A and distilled polythiol compositions of Examples25B-26B and 28B-29B were analyzed using gas chromatography (GC) and datapresented in area percentages, unless otherwise specified. GC analysisof the sulfur-containing compounds excluded peaks attributed tophosphorus-containing materials.

Table VI summarizes certain process conditions and analytical resultsfor the polythiol compositions of Examples 25-29. Table VI indicatesthat excellent conversion was achieved for Examples 25A-27A, resultingin crude polythiol compositions containing about 0.8-1% ene, about 2-4%mono-S, about 87-89% DPDM, and about 7-9% heavies.

The crude polythiol compositions of Example 25A and 26A were subjected,independently, to laboratory distillation in four smaller batches. Thedistillation conditions were a pressure of 9 torr, a kettle temperatureat reflux in the 127-153° C. range, a head temperature at reflux in the24-42° C. range, a final kettle temperature in the 162-180° C. range,and a final overhead temperature in the 108-152° C. range. The resultantfour distillation (kettle) samples were recombined to form the composite25B and 26B samples, respectively. As shown in Table VI, thedistillation process removed virtually all of the ene and virtually allof the mono-S products, resulting in distilled polythiol compositions25B-26B containing zero ene, less than 0.1% mono-S, about 89-91% DPDM,and about 9-11% heavies. It is believed that due to the removal of thelighter fractions, the distilled products had no offensive odor. Whilenot wishing to be bound by the following theory, it is believed thatfurther advancement to sulfide heavies may be occurring in thedistillation process, in addition to simply removing the lighterfraction from the crude polythiol composition.

Additional distillation experiments were performed on a polythiolcomposition produced similarly to Examples 25A-27A. Example 28B wasproduced at 9-10 torr, while Example 29B was produced at 21 torr. Asshown in Table VI, the distilled polythiol compositions of Examples28B-29B containing zero ene, less than 1% mono-S, about 90% DPDM, andabout 9-10% heavies.

Examples 30-37 Flotation Recovery of Mining Chemicals

The procedures for the evaluation of different ores and the flotationrecovery of various metals are different, but each generally starts witha grind size determination to determine the desired grind time to give asample with the correct particle size distribution according to the USStandard mesh scale. An appropriate amount of ore from the appropriatemine (900 to 1000 grams, depending on the ore) was provided at the −10mesh size. This ore was placed in a rod mill with 20 lb of rods withprescribed sizes, and an appropriate amount of water was added to givethe desired solids content. The rod mill was turned on for the desiredamount of time. This time was based on prior knowledge of that oresample or an educated guess based on experience of similar orematerials. After grinding for the desired amount of time, the sample waspoured and rinsed with a minimum amount of tap water into a container.The water and solids were poured through a 230 mesh wet screen sieveshaker while washing with water to remove any fines. This was done intwo batches to facilitate the washing procedure. Failure to remove thefines often can result in the material being glued together in chunks,analogous to concrete. The remaining solids were removed from the screenwith washing onto filter paper in a Buchner funnel with vacuum. Thesolids collected were dried in an oven overnight at 75° C. The driedsolids were then screened through a series of screens (25 mesh, 40, 50,70, 100, 140, 200, 230, and Pan) on a Ro-Tap® shaker in two batches, sixminutes each. A total of three or more grind experiments were requiredto bracket the desired grind time and give a graph of time vs. wt. % drysolids on a certain mesh screen size.

For example, the grind size was 30 wt. %+100 mesh solids (meaning 30% ofthe particles are 149 microns or larger) for Ore 1, 36 wt. %+100 meshsolids (meaning 36% of the particles are 149 microns or larger) for Ore3, 20 wt. %+100 mesh solids (meaning 20% of the particles are 149microns or larger) for Ore 4, and 25 wt. %+70 mesh solids (meaning 25%of the particles are larger than 210 microns) for Ore 2. The +100 meanseverything collected on the 100 screen and larger (such as 25, 40,etc.). From the linear plot of this data, the ideal grind time wasdetermined by adding the amount of solids on the screens up to thedesired mesh size. From the plot of this data, the desired grind timewas read. This procedure can be done periodically, but is necessary ifthe ore type or the rod charge changes.

The compositions of each ore evaluated herein are summarized in TableVII. Values are shown in wt. % for copper, iron, molybdenum, sulfur, andtotal insolubles.

The standard flotation procedure for Ore 1 chalcopyrite is as follows. A1-kg charge of Ore 1 was added to a rod mill along with 650 mL tap waterand approximately 1 g of lime (this amount can be adjusted to obtain thedesired alkalinity, see below). The flotation collector reagents wereadded to the pool of water (not directly on the solids) in the millusing micro syringes: PAX (potassium amyl xanthate), 0.01 lb/ton @ 1%solution (1000 μL), made fresh daily; medium cycle oil (MCO), 0.05lb/ton, 24.6 μL; MC 37 collector (mixture of TDDM and MCO), 0.05 lb/ton(26.1 μL); and plant frother (80% Nalco NALFLOTE® 9837/20% CytecOREPREP® X-133), 28 μL. The mill was placed on rubber rollers and groundfor the predetermined time. The mill was removed from the rollers andthe solids washed into a transparent plastic flotation cell (2.5 L).Only enough water was used to reach the flotation volume (2-liter markon flotation cell). If too little water was used to wash the materialinto the flotation cell, additional lime water was added to reach the2-liter flotation volume. The solids amount was about 32 wt. % forOre 1. The material was conditioned for two min at 1200 rpm, thenfloated for five min at 1200 rpm. Air was bubbled into solution at therate of 8 L/min. Froth was removed from the surface of the cellapproximately every 10 sec with a plastic paddle. The froth wascollected in a glass pan under the lip of the cell. Liquid was addedperiodically to keep the solution near the lip of the cell so frothcould be easily removed. Care was taken to not have froth flow over thelip without raking with the paddle. The standpipe and back cell cornerswere washed down as needed with lime water. Depending on the frothinessof the ore, it may be necessary to restrict the air at the beginning ofthe flotation to prevent froth from overflowing the cell on its own.Generally, the air valve was completely open by the end of the firstminute. If not, then the amount of frother was adjusted. If it wasdifficult to maintain complete surface coverage with froth, a few moremicroliters of frothing agent were added. To do this, the air and timerwere shut off, the froth concentrate added and conditioned for 30 secbefore turning back on the air and timer.

The air and stirring were turned off and the apparatus washed to removesolids from the stirrer and shaft into the flotation cell. Afterallowing the solids to settle for a few minutes, a sample was taken fortitration to determine alkalinity. The remaining tails were filteredthrough an 8 inch stainless steel filter (3 gal) onto shark skin filterpaper. The collected solids were dried in an oven at 85° C. overnight togive dry solids that were weighed and labeled as tailings.

The rougher froth concentrate collected in the pan was filtered bywashing onto filter paper and dried in an oven at 85° C. overnight.Temperature was kept at/below 85° C. to prevent oxidation and weightchanges from occurring. The dried solids were weighed and labeled asconcentrate. Both the tailings and concentrate were analyzed fordetermination of copper, molybdenum, and iron.

The alkalinity titration procedure defined an alkalinity of 1.0 as beingequivalent to 0.01 lb of CaO per ton of solution. To prepare lime waterof 30 alkalinity, 19 g of CaO were added to 50 L of water, agitated forat least one hour, then solids were settled overnight. The lime waterwas decanted for use. For titration, to a 50 mL alkaline solution, onedrop of phenolphthalein indicator solution was added, and titrated with0.02N H₂SO₄ solution until the pink color disappeared. Each mL oftitrating solution equaled 2.0 alkalinity units.

Assuming a solution is 30 alkalinity, that is, 0.3 lb CaO per ton ofsolution, then, (0.3 lb CaO/ton solution)*(ton/2000 lb)*(8.345lb/gal)*(gal/3.785 L)*(453.6 g/lb) converts to 0.15 g CaO/L, or 0.0075 gCaO/50 mL.

If the molecular weight of CaO=56 g/mol, and the molecular weight ofH₂SO₄=98 g/mol, and N=(Molarity)*(net positive charge), then0.02NH₂SO₄=(0.02/2)*(98 g/mol)=(0.98 g/L)*(1 L/1000 mL)=0.00098 g/mL.

According to the stoichiometry of the reaction:CaO+H₂SO₄═CaSO₄+H₂O,then 98 g H₂SO₄ neutralizes 56 g CaO.

If 0.0075 g CaO are present, then 0.0075×98/56=0.013125 gm H₂SO₄ arerequired, and 0.013125 g H₂SO₄/0.00098 g/mL=13.393 mL H₂SO₄.

The standard flotation procedure for Ore 2 is as follows. The grind sizewas determined as described hereinabove for Ore 1. The optimum grindtime was 9 min. One kg bag of ore was charged and 650 mL of water wasadded to the rod mill. The flotation procedure was carried out asdescribed for the Ore 1, except a time of 9 min was used for the new oreand 12 min 18 sec for the old ore. The standard collector system forthis ore was added to the grind: 14 μL of Cytec AERO® MX 7021 and 12.5μL of Cytec AERO® XD 5002—both of which are modified thionocarbamates.The frother added in the flotation cell was Cytec OREPREP® X-133 at 5.6μL dosage. The pH was adjusted to 11 with lime and the mixer was startedat 1200 rpm for 1 min during the conditioning phase. The air was startedand the froth was scraped for 6 min into one pan. The air was turned offand the final pH was checked. The concentrate and tailings materialswere filtered, dried and weighed as described for the Ore 1 process.

The standard flotation procedure for Ore 3 is as follows. The grind sizewas determined as described hereinabove for Ore 1. The optimum grindtime was 5 min 7 sec. A 900-g charge of ore, 0.6 g of lime, 32.5 μL ofdiesel, and 600 mL of water were charged into the rod mill. The optimumgrind time was utilized and the material transferred to the flotationcell as described above in the Ore 1 procedure. Then, 1091 μL of a 1%solution of sodium ethyl xanthate and 28 μL of the 80/20 frothermentioned in the Ore 1 procedure were charged to the stirring liquid andconditioned for one min. The froth was collected for 3 min into acollection pan. The air was stopped and another 28 μL of frother and 546μL of 1% sodium ethyl xanthate were added to the slurry. The air wasrestarted and a 1-min conditioning phase was performed. The froth wasthen collected for another 2 min into the collection. The concentrateand tailings material were filtered, dried and weighed as described forthe Ore 1 process.

The standard flotation procedure for Ore 4 is as follows. The grind sizewas determined as described hereinabove for Ore 1, except the desiredgrind for Ore 4 was 20% plus 100 mesh (meaning 20% of the particles are149 microns or larger). The optimum grind time to achieve these resultswas 13.75 min. A 1-kg charge of ore was utilized. The amount of limeadded to the grind was 1.2 g along with 500 μL of thePAX/dithiophosphate (DTP) 238 solution. The PAX/DTP 238 solution wasprepared by mixing 153 mL of distilled water with 0.5 mL DTP 238 and 0.5gram of PAX. The pH of the slurry was 10.5 after diluting with 650 mL ofwater and transferring to the flotation cell and diluting with water upto the 2-L mark. The slurry was stirred without air and 2000 μL ofPAX/DTP 238 solution were added along with 34 μL of a 50/50 vol. mixtureof pine oil/MIBC. The pulp was stirred at 1200 rpm for one min and thenthe 8 L/min air was turned on. The froth was then raked over the weirfor 3 min into a pan. The air was turned off and an additional 34 μL ofpine oil/MIBC (frother) and 2000 μL of PAX/DTP were added followed byconditioning for 1 min. The air was then turned back on and the frothcollected for an additional 3 min into the pan. The air was then turnedoff while adding another 34 μL of pine oil/MIBC and 2000 μL of PAX/DTPfollowed by conditioning for 1 min while stirring. The air was thenturned on for another min, followed by collecting the froth for 3 min.The air and stirring were then turned off and the concentrate pan wasremoved and the pulp mixture vacuum filtered to give the concentratethat was then dried in an oven overnight at 85° C. The tailings mixturewas then poured out into a filter with filter paper to obtain a wettailings mixture. This mixture was dried in an oven overnight at 85° C.The weight of the concentrate and tailings were recorded beforeanalytical analysis.

Table VIII summarizes Examples 30-37 and the wt. % recoveries of copper,molybdenum, and iron from the four ores tested, using the standardmining chemical collector for each ore and a polythiol composition ofthis invention at different amounts. Duplicates of each flotationexperiment were conducted, and the average reported. The polythiolcomposition used was a composite, low odor, polythiol compositionsimilar in components and amounts to that of Examples 25B-26B and28B-29B. The polythiol composition used in the flotation testing(Examples 31, 33, 35, and 37) contained zero ene, less than 0.1% mono-Scompounds, 90-91% DPDM compounds, and 9-10% heavies.

The standard for Ore 1 (Example 32) was a collector composition (per tonbasis) containing 1200 g of lime, 1000 μL of 1% potassium amyl xanthate(PAX), 25 μL of medium cycle oil (MCO), 26 μL of MC 37 (mixture of TDDMand MCO), and 28 μL of plant frother 80% Nalco NALFLOTE® 9837/20% CytecOREPREP® X-133. Example 33 for Ore 1 used a collector compositioncontaining 1200 g of lime, 9 μL of the polythiol composition, and 28 μLof plant frother 80% Nalco NALFLOTE® 9837/20% Cytec OREPREP® X-133.

The standard for Ore 3 (Example 30) was a collector composition (per tonbasis) containing 600 g of lime, 1637 μL of a 1% sodium ethyl xanthatesolution in water, 32.5 μL of diesel, and 56 μL of pine oil/MIBC(frother). Example 31 for Ore 3 used a collector composition containing600 g of lime, 5 μL of the polythiol composition, and 56 μL of pineoil/MIBC (frother).

The standard for Ore 2 (Example 34) was a collector composition (per tonbasis) containing 600 g of lime, 12.5 μL of thionocarbamate Cytec AERO®XD 5002, 14 μL of thionocarbamate MX 7021, and 20 μL of frother CytecAERO® X-133. Example 35 for Ore 2 used a collector compositioncontaining 600 g of lime, 20 μL of the polythiol composition, and 20 μLof Cytec OREPREP® X-133 (frother).

The standard for the Ore 4 (Example 36) was a collector composition (perton basis) containing 1100 g of lime, 6500 μL of 1% PAX/DTP 238, and 102μL of pine oil/MIBC (frother). Example 37 for the Ore 4 used a collectorcomposition containing 1100 g of lime, 15 μLthe polythiol composition,and 102 μL of pine oil/MIBC (frother).

As shown in Table VIII, and unexpectedly, the collector compositionsused in Examples 31 and 33 (containing polythiol compositions disclosedherein) had % recoveries of copper and molybdenum, independently, ofover 90 wt. %. Moreover, and quite surprisingly, the % recoveries ofcopper and molybdenum in Example 33 were comparable to the mine standardof Example 32, and the % recoveries of copper and molybdenum in Example31 were superior to the mine standard of Example 30.

The collector compositions used in Examples 35 and 37 were successful inrecovering significant percentages of copper and molybdenum, but werenot as efficient as the current mine standards for Ore 2 and Ore 4.

In addition to the testing results summarized in Table VIII, experimentssimilar to Example 33 were performed, but with 18 μL of the polythiolcomposition, and the % recoveries for Cu, Mo, and Fe were 90.3%, 91.2%,and 28.2%, respectively. Additional experiments similar to Example 31also were performed, but with 9 or 18 μL of the polythiol composition,and the % recoveries for Cu, Mo, and Fe ranged from 93-96%, 92-96%, and44-46%, respectively. Additional experiments similar to Example 35 alsowere performed, but with 10 or 40 μL of the polythiol composition, andthe % recoveries for Cu, Mo, and Fe ranged from 50-76%, 63-67%, and12-26%, respectively. And lastly, additional experiments similar toExample 37 were performed, but with 25 μL of the polythiol composition,and the % recoveries for Cu, Mo, and Fe were 78.6%, 63.0%, and 40.7%,respectively.

Examples 38-43 Flotation Recovery of Mining Chemicals

The flotation experiments of Examples 38-43 were performed similarly toExample 33 (containing a polythiol composition). As shown in Table IX,Examples 38-42 substituted TDDM and Example 43 substituted NDDM in placeof the polythiol composition used in Example 33. Unexpectedly, thecollector composition used in Example 33 (containing a polythiolcomposition disclosed herein) had % recoveries of copper and molybdenum,comparable to that of that of mining collector compositions containingeither TDDM (tertiary dodecyl mercaptan) or NDDM (n-dodecyl mercaptan),under the same flotation conditions.

TABLE I Calculated product characteristics for polythiol componentsderived from limonene. N —SH —S— Total S MW % SH % Sulfide % Total SRatio SH/S SHEW 1 2 0 2 204.3 31.37 0.00 31.37 — 102.2 2 2 1 3 374.517.11 8.56 25.67 2.00 187.4 3 2 2 4 544.7 11.76 11.76 23.53 1.00 272.5 42 3 5 714.9 8.96 13.44 22.41 0.67 357.7 5 2 4 6 885.1 7.24 14.48 21.720.50 442.8 6 2 5 7 1055.3 6.07 15.18 21.25 0.40 528.0 7 2 6 8 1225.65.23 15.69 20.91 0.33 613.2 8 2 7 9 1395.8 4.59 16.07 20.66 0.29 698.3 92 8 10 1566.0 4.09 16.37 20.46 0.25 783.5 N is the number of substitutedcyclohexyl moieties, —SH is the number of thiol groups, —S— is thenumber of sulfide groups, Total S is the total number of sulfur atoms,MW is the molecular weight of the polythiol compound (g/mol), % SH isthe wt. % thiol sulfur, % Sulfide is the wt. % sulfide sulfur, % Total Sis the wt. % sulfur, Ratio SH/S is the ratio of wt. % thiol sulfur towt. % sulfide sulfur, and SHEW is the mercaptan equivalent weight.

TABLE II Calculated product characteristics for illustrative polythiolcompositions derived from limonene. N = 1 99.7 90 85 85 75 N = 2 0.3 1015 13 18 N = 3 0 0 0 2 5 N = 4 0 0 0 0 2 N = 5 0 0 0 0 0 N = 6 0 0 0 0 0% SH 31.3 29.9 29.2 29.1 27.4 % Sulfide 0.03 0.86 1.28 1.35 2.40 RatioSH/S 1220 35 23 22 11 % Total S 31.4 30.8 30.5 30.5 29.8 SHEW 102.3107.1 109.7 110.1 117.1 N is the number of substituted cyclohexylmoieties, % SH is the wt. % thiol sulfur of the composition, % Sulfideis the wt. % sulfide sulfur of the composition, % Total S is the wt. %sulfur of the composition, Ratio SH/S is the ratio of wt. % thiol sulfurto wt. % sulfide sulfur of the composition, and SHEW is the mercaptanequivalent weight of the composition.

TABLE III Polythiol compositions of Examples 1-8. Example 1 2 3 4 5 6 78 Wt. % TEP 0.00 0.45 0.45 0.45 0.23 0.00 0.45 0.45 Wt. % Irgacure 5000.00 0.45 0.45 0.00 0.23 0.00 0.00 0.00 H₂S:olefin ratio 15 15 15 15 1515 15 15 Time (min) 105 17 15 15 15 85 33 30 % Conv. (Raman) 95.9 94.694.1 94.8 — 90.5 — 97.9 GC Analysis % ene 1.24 1.54 1.17 1.26 1.30 2.151.28 1.26 % mono-S 6.98 1.72 3.52 1.93 9.51 18.98 3.05 1.93 % DPDM 85.2189.04 87.87 90.04 81.15 72.95 87.67 90.04 % heavies 6.57 7.70 7.44 6.776.10 4.46 6.01 6.77 Source of limonene Treatt Treatt Or. Terp. 1 Or.Terp. 1 Or. Terp. 2 Or. Terp. 2 Or. Terp. 2 Or. Terp. 2 GC Analysisrepresents area under the curve (area %), which is comparable to wt. %.

TABLE IV Polythiol compositions of Examples 9-16. Example 9 10 11 12 1314 15 16 Phosphite none TBP TBP TBP TBP TBP TBP TBP Wt. % Phosphite 0.000.41 1.35 0.81 0.10 0.10 0.15 0.27 Wt. % Irgacure 500 0.00 0.00 0.000.00 1.00 0.50 0.30 0.27 H₂S:olefin ratio 15 15 15 15 15 15 15 15 Time(min) 120 120 40 45 40 50 40 50 % Conversion 91 92 99 100 99 96 96 97 %Total S 28.7 28.9 29.9 30.0 29.9 30.1 29.9 29.5 GC Analysis % ene 1.621.29 0.78 0.91 0.99 1.41 1.00 0.97 % mono-S 17.19 15.14 2.24 1.94 3.163.47 3.76 4.54 % DPDM 76.06 78.11 89.95 88.96 88.89 88.16 89.07 87.51 %heavies 5.13 5.46 7.03 8.19 6.96 6.96 6.17 6.98 GC Analysis representsarea under the curve (area %), which is comparable to wt. %.

TABLE V Polythiol compositions of Examples 17-24. Example 17 18 19 20 2122 23 24 Phosphite none none TBP TBP TBP TBP TBP TBP Wt. % Phosphite0.00 0.00 0.10 0.10 0.27 0.27 0.27 0.27 Wt. % Irgacure 500 0.00 1.001.00 1.00 0.27 0.27 0.27 0.27 H₂S:olefin ratio 15 15 15 15 15 15 15 15Time (min) 120 95 40 40 50 50 30 40 % Conversion 91 99 99 99 97 97 99 98% Total S 28.7 29.8 29.9 29.7 29.5 29.1 29.1 29.1 GC Analysis % ene 1.621.10 0.99 1.02 0.97 1.16 0.79 0.98 % mono-S 17.19 4.33 3.16 2.31 4.545.74 1.82 2.80 % DPDM 76.06 88.08 88.89 89.85 87.51 87.19 87.63 89.83 %heavies 5.13 6.49 6.96 6.82 6.98 5.91 9.76 6.39 GC Analysis representsarea under the curve (area %), which is comparable to wt. %.

TABLE VI Polythiol compositions of Examples 25-29. Example 25A 25B 26A26B 27A 28B 29B Wt. % TEP 0.50 0.50 0.50 Wt. % Irgacure 500 — — —H₂S:olefin ratio 15 15 15 Time (min) 105 (75) 80 60 % Conversion 97 9597 GC Analysis % ene 0.80 0.00 0.80 0.00 0.98 0.00 0.00 % mono-S 3.320.04 2.63 0.06 2.95 0.39 0.56 % DPDM 88.72 90.51 87.89 89.92 87.97 90.2290.08 % heavies 7.25 9.45 8.67 10.02 8.10 9.39 9.35 GC Analysisrepresents area under the curve (area %), which is comparable to wt. %.

TABLE VII Ore composition summary (wt. %). Ore Cu Fe Mo S Insolubles Ore2 0.48 2.70 0.010 0.97 90.5 Ore 3 0.34 2.28 0.024 1.03 91.5 Ore 1 0.262.99 0.039 0.98 82.7 Ore 4 0.42 2.28 0.009 1.59 77.7

TABLE VIII Summary of the mining chemical collector experiments ofExamples 30-37. Recoveries % Grade % Ore Example Cu Mo Fe Cu Mo DosageOre 3 30 - Standard 92.8 93.7 38.7 4.8 0.34 31 - Polythiol 95.2 94.840.2 5.0 0.31  5 μL Ore 1 32 - Standard 91.2 92.8 24.4 9.7 1.37 33 -Polythiol 91.1 92.4 16.5 7.4 1.15  9 μL Ore 2 34 - Standard 88.8 72.133.3 9.3 0.14 35 - Polythiol 75.6 66.1 27.7 6.5 0.13 20 μL Ore 4 36 -Standard 89.9 67.3 48.9 3.5 0.06 37 - Polythiol 81.4 65.5 44.8 5.6 0.1015 μL

TABLE IX Summary of the mining chemical collector experiments ofExamples 33 and 38-43. Recoveries % Grade % Ore Example Cu Mo Fe Cu MoDosage Ore 1 33 - Polythiol 91.1 92.4 16.5 7.4 1.15 9 μL Ore 1 38 -TDDM91.2 93.7 17.6 11.4 1.84 5 μL Ore 1 39 - TDDM 91.3 93.7 18.5 10.2 1.62 9μL Ore 1 40 - TDDM 89.9 90.1 13.0 7.8 1.15 3 μL Ore 1 41 - TDDM 90.990.7 13.9 7.2 1.02 7 μL Ore 1 42 - TDDM 91.9 93.0 16.0 7.1 1.03 15 μL Ore 1 43 - NDDM 91.1 92.2 18.9 8.0 0.99 26 μL 

The invention is described above with reference to numerous aspects andembodiments, and specific examples. Many variations will suggestthemselves to those skilled in the art in light of the above detaileddescription. All such obvious variations are within the full intendedscope of the appended claims. Other embodiments of the invention caninclude, but are not limited to, the following (embodiments aredescribed as “comprising” but, alternatively, can “consist essentiallyof” or “consist of”):

Embodiment 1

A polythiol composition comprising sulfur-containing compounds, thesulfur-containing compounds comprising:

(i) dipentene dimercaptan compounds;

(ii) at least 4% of a heavy fraction comprising intermolecular sulfidecompounds having at least one (and often, two) thiol sulfur group (—SH),at least one intermolecular sulfide group (—S—), and at least twosubstituted cyclohexyl groups.

Embodiment 2

The polythiol composition of embodiment 1, wherein the heavy fractioncomprises a compound having one of the following structures:

or combinations thereof.

Embodiment 3

The polythiol composition of embodiment 1 or 2, wherein the heavyfraction comprises a compound having one of the following structures:

or combinations thereof.

Embodiment 4

The polythiol composition of any one of the preceding embodiments,wherein the sulfur-containing compounds of the polythiol compositionhave an amount of the heavy fraction (comprising intermolecular sulfidecompounds) in any range disclosed herein, e.g., at least 5%, at least6%, from 4% to 25%, from 4% to 15%, from 5% to 20%, or from 5% to 15%.

Embodiment 5

The polythiol composition of any one of the preceding embodiments,wherein the sulfur-containing compounds of the polythiol compositionhave an amount of the dipentene dimercaptan compounds in any rangedisclosed herein, e.g., from 50% to 95%, from 60% to 95%, from 60% to92%, from 60% to 90%, from 70% to 92%, or from 80% to 92%.

Embodiment 6

The polythiol composition of any one of the preceding embodiments,wherein the sulfur-containing compounds of the polythiol compositionhave a maximum amount of monosulfur compounds in any range disclosedherein, e.g., less than or equal to 5%, less than or equal to 4%, lessthan or equal to 1%, less than or equal to 0.5%, or less than or equalto 0.25%.

Embodiment 7

The polythiol composition of embodiment 6, wherein the monosulfurcompounds comprise a compound having the structure:

Embodiment 8

The polythiol composition of embodiment 6, wherein the monosulfurcompounds comprise a compound having the structure:

Embodiment 9

The polythiol composition of any one of the preceding embodiments,wherein the polythiol composition has a maximum amount of sulfur-freeolefin-containing compounds in any range disclosed herein, e.g., lessthan or equal to 2%, less than or equal to 1%, less than or equal to0.5%, or less than or equal to 0.1%.

Embodiment 10

The polythiol composition of any one of the preceding embodiments,wherein the sulfur-containing compounds comprise:

from 60% to 95% (or from 70% to 92%) of the dipentene dimercaptancompounds;

from 4% to 25% (or from 5% to 15%) of the heavy fraction (comprisingintermolecular sulfide compounds); and

less than or equal to 4% (or less than or equal to 1%) of the monosulfurcompounds.

Embodiment 11

The polythiol composition of any one of the preceding embodiments,wherein the sulfur-containing compounds of the polythiol compositionhave an average weight percentage of thiol sulfur (—SH) in any range ofaverage weight percentages of thiol sulfur disclosed herein, e.g., from27 to 30.5 wt. %, from 29 to 30.5 wt. %, from 28 to 30.3 wt. %, or from29 to 30.2 wt. %.

Embodiment 12

The polythiol composition of any one of the preceding embodiments,wherein the sulfur-containing compounds of the polythiol compositionhave an average weight percentage of sulfide sulfur (—S—) in any rangeof average weight percentages of sulfide sulfur disclosed herein, e.g.,from 0.25 to 5 wt. %, from 0.5 to 5 wt. %, from 0.5 to 3 wt. %, or from0.75 to 4 wt. %.

Embodiment 13

The polythiol composition of any one of the preceding embodiments,wherein the sulfur-containing compounds of the polythiol compositionhave an average thiol sulfur (—SH) to sulfide sulfur (—S—) weight ratioin any range of average thiol sulfur to sulfide sulfur weight ratiosdisclosed herein, e.g., from 3:1 to 100:1, from 5:1 to 75:1, or from10:1 to 50:1.

Embodiment 14

The polythiol composition of any one of the preceding embodiments,wherein the sulfur-containing compounds of the polythiol compositionhave a SHEW in any range of SHEW's disclosed herein, e.g., from 104 to125 g/eq, from 104 to 120 g/eq, from 105 to 125 g/eq, or from 105 to 120g/eq.

Embodiment 15

The polythiol composition of any one of the preceding embodiments,wherein the polythiol composition does not have an offensive odor (orthe sulfur-containing compounds of the polythiol composition do not havean offensive odor).

Embodiment 16

The polythiol composition of any one of the preceding embodiments,wherein the polythiol composition is produced by a process comprising:

1) contacting:

-   -   a) limonene;    -   b) H₂S; and    -   c) optionally, a phosphite compound; and

2) forming the polythiol composition;

wherein a molar ratio of H₂S to carbon-carbon double bonds of thelimonene is in a range from 2:1 to 500:1.

Embodiment 17

The composition of embodiment 16, wherein the process further comprisesa step of removing at least a portion of the H₂S, of the phosphitecompound (if used), of the limonene, of monosulfur compounds, orcombinations thereof, from the polythiol composition.

Embodiment 18

The composition of embodiment 17, wherein the H₂S, the phosphitecompound (if used), the limonene, the monosulfur compounds, orcombinations thereof, are removed by wiped film evaporation,distillation, short path distillation, or a combination thereof.

Embodiment 19

The composition of any one of embodiments 16-18, wherein the molar ratioof H₂S to carbon-carbon double bonds of the limonene is in any range ofmolar ratios of H₂S to carbon-carbon double bonds disclosed herein,e.g., from 2:1 to 150:1, from 2:1 to 50:1, from 3:1 to 50:1, from 5:1 to35:1, or from 8:1 to 25:1.

Embodiment 20

The composition of any one of embodiment 16-19, wherein a molar ratio ofthe phosphite compound to carbon-carbon double bonds of the limonene isin any range of molar ratios of the phosphite compound to carbon-carbondouble bonds disclosed herein, e.g., from 0.0005:1 to 0.10:1, or from0.005:1 to 0.05:1.

Embodiment 21

The composition of embodiment 20, wherein the phosphite compoundcomprises a compound having the formula, P(OR¹)₃, wherein each R¹ isindependently any C₁-C₁₀ hydrocarbyl group disclosed herein.

Embodiment 22

The composition of embodiment 20, wherein the phosphite compoundcomprises trimethylphosphite, triethylphosphite, tributylphosphite, orany combination thereof.

Embodiment 23

The composition of any one of embodiments 16-22, wherein the polythiolcomposition is formed at a temperature in any range of temperaturesdisclosed herein, e.g., from −30° C. to 150° C., from −20° C. to 130°C., from −10° C. to 100° C., from −5° C. to 80° C., or from 0° C. to 60°C.

Embodiment 24

The composition of any one of embodiments 16-23, wherein the polythiolcomposition is formed in the presence of electromagnetic radiation.

Embodiment 25

The composition of any one of embodiments 16-23, wherein the polythiolcomposition is formed in the presence of ultraviolet light.

Embodiment 26

The composition of any one of embodiments 16-23, wherein the polythiolcomposition is formed in the presence of ultraviolet light and aphotoinitiator, and wherein the photoinitiator is present at an amountwithin any weight percentage range disclosed herein, e.g., less than orequal to 5 wt. %, less than or equal to 3 wt. %, less than or equal to 2wt. %, or less than or equal to 1.5 wt. %, based on the weight of thelimonene.

Embodiment 27

The composition of any one of embodiments 16-23, wherein the polythiolcomposition is formed in the presence of a free radical initiator, andwherein the free radical initiator is present at an amount within anyweight percentage range disclosed herein, e.g., from 0.1 to 9 wt. %, orfrom 0.1 to 2 wt. %, based on the weight of the limonene.

Embodiment 28

The composition of embodiment 27, wherein the polythiol composition isformed at conditions suitable for a thermal decomposition of the freeradical initiator.

Embodiment 29

The composition of any one of embodiments 16-28, wherein the polythiolcomposition is formed in the presence of any solvent disclosed herein,e.g., a hydrocarbon solvent, an aromatic hydrocarbon solvent, a ketonesolvent, an alcohol solvent, an ether solvent, or any combinationthereof.

Embodiment 30

The composition of any one of embodiments 16-29, wherein at least 90%,at least 95%, or at least 98%, of the carbon-carbon double bonds of thelimonene have reacted to form a sulfur-containing group.

Embodiment 31

A collector composition comprising the polythiol composition of any oneof embodiments 1-30.

Embodiment 32

A collector composition comprising water and the polythiol compositionof any one of embodiments 1-30.

Embodiment 33

A collector composition comprising the polythiol composition of any oneof embodiments 1-30 and any suitable pH control agent or any pH controlagent disclosed herein, e.g., a carbonate compound, or lime.

Embodiment 34

A collector composition comprising the polythiol composition of any oneof embodiments 1-30 and any suitable frothing agent or any frothingagent disclosed herein, e.g., MIBC, methyl isobutyl carbinol, pine oil,NALFLOTE® 9837, Cytec OREPREP® X-133, etc., or any combination thereof.

Embodiment 35

A collector composition comprising the polythiol composition of any oneof embodiments 1-30, a frothing agent, a pH control agent, and water.

Embodiment 36

The collector composition of any one of embodiments 32-35, wherein thecollector composition further comprises any (second) suitable collectoragent or any second collector agent disclosed herein, e.g., a xanthate,a xanthic ester, a thionocarbonate, a dialkyl dithiophosphate, etc., orany combination thereof.

Embodiment 37

A flotation process for the recovery of a metal from an ore, the processcomprising contacting the ore with the collector composition of any oneof embodiments 32-36 or the polythiol composition of any one ofembodiments 1-30.

Embodiment 38

The process of embodiment 37, wherein the metal comprises a transitionmetal.

Embodiment 39

The process of embodiment 37, wherein the metal comprises gold, silver,platinum, copper, nickel, iron, lead, zinc, molybdenum, cobalt,chromium, or combinations thereof.

Embodiment 40

The process of embodiment 37, wherein the metal comprises copper.

Embodiment 41

The process of embodiment 37, wherein the metal comprises molybdenum.

Embodiment 42

The process of any one of embodiments 37-41, wherein the ore comprises acopper-bearing ore and/or a molybdenum-bearing ore.

Embodiment 43

The process of any one of embodiments 37-41, wherein the ore compriseschalcopyrite.

Embodiment 44

The process of any one of embodiments 37-41, wherein the ore compriseschalcocite.

Embodiment 45

The process of any one of embodiments 37-44, wherein the polythiolcomposition and the ore are contacted at a weight ratio in a range fromabout 0.001 lb of polythiol composition per ton of ore to about 5 lb ofpolythiol composition per ton of ore.

Embodiment 46

The process of any one of embodiments 37-45, wherein the % recovery ofcopper and/or molybdenum is at least about 80 wt. %, at least about 85wt. %, or at least about 90 wt. %.

Embodiment 47

The process of any one of embodiments 37-46, wherein the % recovery ofcopper and/or molybdenum is greater than a mine standard, or withinabout 2 wt. %, or within about 1 wt. %, of a mine standard, under thesame flotation conditions.

Embodiment 48

The process of any one of embodiments 37-47, wherein the % recovery ofcopper and/or molybdenum is greater than that of TDDM or NDDM, or withinabout 2 wt. %, or within about 1 wt. %, of the % recovery using TDDM orNDDM, under the same flotation conditions.

We claim:
 1. A flotation process for the recovery of a metal from anore, the process comprising: contacting the ore with a collectorcomposition, wherein the collector composition comprises a polythiolcomposition comprising sulfur-containing compounds, thesulfur-containing compounds comprising: (i) dipentene dimercaptancompounds; and (ii) at least 4 wt. % of a heavy fraction comprisingintermolecular sulfide compounds having at least one thiol sulfur group(—SH), at least one intermolecular sulfide group (—S—), and at least twosubstituted cyclohexyl groups.
 2. The process of claim 1, wherein theheavy fraction comprises intermolecular sulfide compounds having twothiol sulfur groups (—SH), one intermolecular sulfide group (—S—), andtwo substituted cyclohexyl groups.
 3. The process of claim 1, whereinthe heavy fraction comprises intermolecular sulfide compounds having twothiol sulfur groups (—SH), two intermolecular sulfide groups (—S—), andthree substituted cyclohexyl groups.
 4. The process of claim 1, whereinthe sulfur-containing compounds contain from 60 wt. % to 95 wt. %dipentene dimercaptan compounds.
 5. The process of claim 4, wherein thepolythiol composition contains less than or equal to 1 wt. % sulfur-freeolefin-containing compounds.
 6. The process of claim 1, wherein thesulfur-containing compounds contain: from 5 wt. % to 20 wt. % heavyfraction; and less than or equal to 4 wt. % monosulfur compounds.
 7. Theprocess of claim 1, wherein the sulfur-containing compounds arecharacterized by: an average thiol sulfur to sulfide sulfur weight ratioin a range from 3:1 to 100:1; an average of from 0.25 wt. % to 5 wt. %sulfide sulfur; an average of from 27 wt. % to 30.5 wt. % thiol sulfur;a mercaptan equivalent weight in a range from 104 to 120 g/eq; or anycombination thereof.
 8. The process of claim 1, wherein the metalcomprises gold, silver, platinum, copper, nickel, iron, lead, zinc,molybdenum, cobalt, chromium, or combinations thereof.
 9. The process ofclaim 1, wherein the metal comprises copper, and a percent recovery ofcopper from the ore is at least 85 wt. %.
 10. The process of claim 1,wherein the metal comprises molybdenum, and a percent recovery ofmolybdenum from the ore is at least 85 wt. %.
 11. The process of claim1, wherein the collector composition and the ore are contacted at anamount of the polythiol composition per ton of ore in a range from about0.001 lb to about 5 lb.
 12. The process of claim 1, wherein the orecomprises a copper-bearing ore and/or a molybdenum-bearing ore.
 13. Theprocess of claim 1, wherein the process is characterized by; a percentrecovery of copper from the ore that is greater than or within about 2wt. % of a mine standard for the ore, under the same flotationconditions; a percent recovery of molybdenum from the ore is greaterthan or within about 2 wt. % of a mine standard for the ore, under thesame flotation conditions; or both.
 14. The process of claim 1, whereinthe process is characterized by; a percent recovery of copper from theore that is greater than or within about 2 wt. % of a percent recoveryusing TDDM instead of the polythiol composition, under the sameflotation conditions; a percent recovery of copper from the ore that isgreater than or within about 2 wt. % of a percent recovery using NDDMinstead of the polythiol composition, under the same flotationconditions; a percent recovery of molybdenum from the ore that isgreater than or within about 2 wt. % of a percent recovery using TDDMinstead of the polythiol composition, under the same flotationconditions; a percent recovery of molybdenum from the ore that isgreater than or within about 2 wt. % of a percent recovery using NDDMinstead of the polythiol composition, under the same flotationconditions; or any combination thereof.
 15. A collector compositioncomprising water and a polythiol composition comprisingsulfur-containing compounds, the sulfur-containing compounds comprising:(i) dipentene dimercaptan compounds; and (ii) at least 4 wt. % of aheavy fraction comprising intermolecular sulfide compounds having atleast one thiol sulfur group (—SH), at least one intermolecular sulfidegroup (—S—), and at least two substituted cyclohexyl groups.
 16. Thecollector composition of claim 15, wherein the sulfur-containingcompounds comprise: from 70 wt. % to 92 wt. % dipentene dimercaptancompounds; from 4 wt. % to 25 wt. % heavy fraction; and less than orequal to 4 wt. % monosulfur compounds.
 17. The collector composition ofclaim 15, wherein the collector composition further comprises a pHcontrol agent.
 18. The collector composition of claim 15, wherein thecollector composition further comprises a frothing agent.
 19. Thecollector composition of claim 15, wherein the collector compositioncomprises water, the polythiol composition, a frothing agent, and a pHcontrol agent.
 20. The collector composition of claim 15, wherein thecollector composition further comprises a second mining chemicalcollector agent.